Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 311
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Eur Radiol ; 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38780766

RESUMO

OBJECTIVES: To establish and evaluate an ultra-fast MRI screening protocol for prostate cancer (PCa) in comparison to the standard multiparametric (mp) protocol, reducing scan time and maintaining adequate diagnostic performance. MATERIALS AND METHODS: This prospective single-center study included consecutive biopsy-naïve patients with suspected PCa between December 2022 and March 2023. A PI-RADSv2.1 conform mpMRI protocol was acquired in a 3 T scanner (scan time: 25 min 45 sec). In addition, two deep-learning (DL) accelerated sequences (T2- and diffusion-weighted) were acquired, serving as a screening protocol (scan time: 3 min 28 sec). Two readers evaluated image quality and the probability of PCa regarding PI-RADSv2.1 scores in two sessions. The diagnostic performance of the screening protocol with mpMRI serving as the reference standard was derived. Inter- and intra-reader agreements were evaluated using weighted kappa statistics. RESULTS: We included 77 patients with 97 lesions (mean age: 66 years; SD: 7.7). Diagnostic performance of the screening protocol was excellent with a sensitivity and specificity of 100%/100% and 89%/98% (cut-off ≥ PI-RADS 4) for reader 1 (R1) and reader 2 (R2), respectively. Mean image quality was 3.96 (R1) and 4.35 (R2) for the standard protocol vs. 4.74 and 4.57 for the screening protocol (p < 0.05). Inter-reader agreement was moderate (κ: 0.55) for the screening protocol and substantial (κ: 0.61) for the multiparametric protocol. CONCLUSION: The ultra-fast screening protocol showed similar diagnostic performance and better imaging quality compared to the mpMRI in under 15% of scan time, improving efficacy and enabling the implementation of screening protocols in clinical routine. CLINICAL RELEVANCE STATEMENT: The ultra-fast protocol enables examinations without contrast administration, drastically reducing scan time to 3.5 min with similar diagnostic performance and better imaging quality. This facilitates patient-friendly, efficient examinations and addresses the conflict of increasing demand for examinations at currently exhausted capacities. KEY POINTS: Time-consuming MRI protocols are in conflict with an expected increase in examinations required for prostate cancer screening. An ultra-fast MRI protocol shows similar performance and better image quality compared to the standard protocol. Deep-learning acceleration facilitates efficient and patient-friendly examinations, thus improving prostate cancer screening capacity.

2.
Eur J Neurol ; 23(9): 1441-6, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27238738

RESUMO

BACKGROUND AND PURPOSE: Theoretical considerations and the results of animal studies indicate that manual lymphatic drainage (MLD) might have an impact on intracranial pressure (ICP). There is a lack of clinically qualitative investigations on patients with severe cerebral diseases. METHODS: Between April 2013 and January 2015 a prospective observational study was performed on patients who were undergoing intracranial pressure measurement and treatment with MLD. ICP, cerebral perfusion pressure, mean arterial pressure (MAP), heart rate and oxygen saturation were recorded continuously 15 min before the procedure, during MLD (22 min) and for 15 min after the procedure. For analysis the data treatment units were divided into two groups: patients with a mean baseline ICP <15 mmHg (group 1) and patients with a mean ICP ≥15 mmHg before MLD (group 2). RESULTS: A total of 133 treatment units (61 patients) were analysed (group 1 n = 99; group 2 n = 34). The mean baseline ICP was 10.4 mmHg overall, and 8.3 mmHg and 18.6 mmHg respectively in group 1 and group 2; ICP significantly decreased during therapy with MLD and this persisted during the follow-up period in group 2. MAP did not show any significant differences between the different periods. CONCLUSIONS: Our data showed a significant reduction of ICP during therapy with craniocervical MLD in patients with severe cerebral diseases.


Assuntos
Encefalopatias/terapia , Encéfalo , Vértebras Cervicais , Pressão Intracraniana , Sistema Linfático , Drenagem Linfática Manual/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encefalopatias/fisiopatologia , Lesões Encefálicas Traumáticas/terapia , Neoplasias Encefálicas/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Resultado do Tratamento , Adulto Jovem
3.
J Chem Phys ; 145(9): 094108, 2016 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-27608990

RESUMO

We investigate wave propagation in rotationally symmetric tubes with a periodic spatial modulation of cross section. Using an asymptotic perturbation analysis, the governing quasi-two-dimensional reaction-diffusion equation can be reduced into a one-dimensional reaction-diffusion-advection equation. Assuming a weak perturbation by the advection term and using projection method, in a second step, an equation of motion for traveling waves within such tubes can be derived. Both methods predict properly the nonlinear dependence of the propagation velocity on the ratio of the modulation period of the geometry to the intrinsic width of the front, or pulse. As a main feature, we observe finite intervals of propagation failure of waves induced by the tube's modulation and derive an analytically tractable condition for their occurrence. For the highly diffusive limit, using the Fick-Jacobs approach, we show that wave velocities within modulated tubes are governed by an effective diffusion coefficient. Furthermore, we discuss the effects of a single bottleneck on the period of pulse trains. We observe period changes by integer fractions dependent on the bottleneck width and the period of the entering pulse train.

4.
Unfallchirurg ; 119(6): 527-31, 2016 Jun.
Artigo em Alemão | MEDLINE | ID: mdl-26597195

RESUMO

Complex injuries of the hand and wrist lead to severe loss of function. Complex trauma of the upper extremities may lead to severe disabilities and therefore meticulous reconstruction is of utmost importance to enable good functional outcome and to assure an adequate quality of life. We demonstrate the case of a patient who suffered from complex bilateral injuries at the wrist level including a subtotal amputation of the left hand and third degree open wrist destruction on the contralateral side. Due to the immediate bilateral operation including the unilateral use of an osteocutaneous free fibula flap, both hands could be salvaged in this case. Severe hand and wrist injuries also require intensive postoperative treatment including intensive physiotherapy, occupational therapy, pain therapy and psychological support to achieve a good functional result.


Assuntos
Amputação Traumática/reabilitação , Amputação Traumática/cirurgia , Traumatismo Múltiplo/reabilitação , Traumatismo Múltiplo/cirurgia , Traumatismos do Punho/reabilitação , Traumatismos do Punho/cirurgia , Cotos de Amputação/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos de Cirurgia Plástica/métodos , Retalhos Cirúrgicos , Resultado do Tratamento
5.
B-ENT ; Suppl 26(1): 107-126, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-29461737

RESUMO

Management of burn wounds of the head and neck region. Management of the severely burned patient is ery often a challenge, not only due to major disturbances in anatomy and physiological processes, but also because the relatively low incidence of this pathology in both civilian and military practice results in care providers'lack of experience. The purpose of this educational document is to provide doctors confronted with these formidable trauma patients with basic management guidelines as well as some practical tips. In summary, and most importantly, these patients should be reated as any other multitrauma patient. First aid is essential and can be provided by non-medical staff. Initial medical nanagement should focus on the usual, familiar trauma algorithms of ABCDEF from the emergency management of evere burns (EMSB) manual' or the ABCDEs of the manual of advanced trauma life support (ATLS)2 or advanced burn life support (ABLS). Medical care should proceed through the following steps - Step one: establish a reliable intravenous nfusion; step two: protect the airway; step three: establish and maintain a haemodynamic state compatible with sufficient organ perfusion in order to reduce aggravation of the burn wounds and increase overall survival likelihood; step four: provide analgesia with adequate sedation and provide anaesthesia for escharotomy, fasciotomy or other surgical injuries; step five: maintain normothermia; step six: feed the patient by starting enteral nutrition as early as possible; step seven: prevent infection using antiseptic wound management, systemic antibiotics and tetanus prophylaxis. All of these intricate steps require continuous reassessment and adjustment, but the existence of other wounds (blast injuries, penetrating and blunt trauma) even further complicates the management of burn casualties.


Assuntos
Antibacterianos/uso terapêutico , Queimaduras/terapia , Traumatismos Craniocerebrais/terapia , Hidratação/métodos , Lesões do Pescoço/terapia , Ressuscitação/métodos , Cuidados de Suporte Avançado de Vida no Trauma , Nutrição Enteral , Fasciotomia , Humanos , Manejo da Dor , Lesão por Inalação de Fumaça/terapia
6.
Clin Nephrol ; 73(6): 454-72, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20497759

RESUMO

Several genetic disorders can present in adult patients with renal insufficiency. Genetic renal disease other than ADPKD accounts for ESRD in 3% of the adult Dutch population. Because of this low prevalence and their clinical heterogeneity most adult nephrologists are less familiar with these disorders. As a guideline to differential diagnosis, we provide an overview of the clinical manifestations and the pathogenesis of the main genetic disorders with chronic renal insufficiency surfacing in adulthood and add an algorithm plus 4 tables. We also indicate where molecular genetics nowadays can be of aid in the diagnostic process. The following disorders are discussed by mode of inheritance: 1) Autosomal dominant: autosomal dominant polycystic kidney disease, nephropathies associated with uromodulin (medullary cystic disease and familial juvenile hyperuricemic nephropathy), renal cysts and diabetes syndrome, nail-patella syndrome, glomerulopathy with fibronectin deposits. 2) Not autosomal dominant: Nephronophthisis, Fabry disease, primary oxalosis, Adenine Phosphoribosyl Transferase deficiency, Alport syndrome, Lecithin-cholesterol acyltransferase deficiency, adult-onset cystinosis.


Assuntos
Doenças Genéticas Inatas/diagnóstico , Falência Renal Crônica/etiologia , Adulto , Humanos
7.
Rev Med Liege ; 65(12): 691-5, 2010 Dec.
Artigo em Francês | MEDLINE | ID: mdl-21287765

RESUMO

Orf is an infection often unknown to practicians throughout the world. The first known cases were registered at the end of the 19th century. The virus affects ovines and caprins and is characterized by cutaneous and/or mucosae lesions. It is strongly resistant and the survival time is important in the outside environment. The morbidity of Orf is far higher than its mortality. The virus is transmitted by direct and indirect contact among humans, who became vectors themselves. Those subjects that are in contact with the animals in question due to professional reasons are at risk in particular. The same goes for attendants and participants of religious feasts. The preferred localization of lesions in humans is the hands. The diagnostic is easily set by the anamnesis and the clinical characteristics of the lesions except when it happens to be a particular form. The complications are nearly exclusively related to the unawareness of the virus in form of inappropriate medical acts. The evolution is spontaneous and the unique treatment is the prophylaxis of bacterial infection as well as a constant surveillance.


Assuntos
Ectima Contagioso/diagnóstico , Ectima Contagioso/terapia , Vírus do Orf/patogenicidade , Animais , Diagnóstico Diferencial , Vetores de Doenças , Ectima Contagioso/transmissão , Humanos , Ovinos , Zoonoses
8.
PLoS One ; 15(7): e0235965, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701960

RESUMO

Secondary lymphedema (SL)is a frequent and devastating complication of modern oncological therapy and filarial infections. A lack of a reliable preclinical model to investigate the underlying mechanism of clinical stage progression has limited the development of new therapeutic strategies. Current first line treatment has shown to be merely symptomatic and relies on lifetime use of compression garments and decongestive physiotherapy. In this study, we present the development of a secondary lymphedema model in 35 rats using pre- and intraoperative fluorescence-guided mapping of the lymphatics and microsurgical induction. In contrast to the few models reported so far, we decided to avoid the use of radiation for lymphedema induction. It turned out, that the model is nearly free of complications and capable of generating a statistically significant limb volume increase by water displacement measurements, sustained for at least 48 days. A translational, accurate lymphatic dysfunction was visualized by a novel VIS-NIR X-ray ICG-Clearance-Capacity imaging technology. For the first-time SL stage progression was validated by characteristic histological alterations, such as subdermal mast cell infiltration, adipose tissue deposition, and fibrosis by increased skin collagen content. Immunofluorescence confocal microscopy analysis suggested that stage progression is related to the presence of a characteristic α SMA+/HSP-47+/vimentin+ fibroblast subpopulation phenotype. These findings demonstrate that the in-vivo model is a reliable and clinically relevant SL model for the development of further secondary lymphedema therapeutic strategies and the analysis of the veiled molecular mechanisms of lymphatic dysfunction.


Assuntos
Corantes Fluorescentes/química , Linfedema/patologia , Microcirurgia/efeitos adversos , Actinas/metabolismo , Animais , Colágeno/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Verde de Indocianina/química , Linfedema/etiologia , Microscopia de Fluorescência , Ratos , Ratos Endogâmicos Lew , Pele/patologia , Vimentina/metabolismo
9.
Biophys J ; 97(4): 992-1002, 2009 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-19686646

RESUMO

Intracellular Ca(2+) release is a versatile second messenger system. It is modeled here by reaction-diffusion equations for the free Ca(2+) and Ca(2+) buffers, with spatially discrete clusters of stochastic IP(3) receptor channels (IP(3)Rs) controlling the release of Ca(2+) from the endoplasmic reticulum. IP(3)Rs are activated by a small rise of the cytosolic Ca(2+) concentration and inhibited by large concentrations. Buffering of cytosolic Ca(2+) shapes global Ca(2+) transients. Here we use a model to investigate the effect of buffers with slow and fast reaction rates on single release spikes. We find that, depending on their diffusion coefficient, fast buffers can either decouple clusters or delay inhibition. Slow buffers have little effect on Ca(2+) release, but affect the time course of the signals from the fluorescent Ca(2+) indicator mainly by competing for Ca(2+). At low [IP(3)], fast buffers suppress fluorescence signals, slow buffers increase the contrast between bulk signals and signals at open clusters, and large concentrations of buffers, either fast or slow, decouple clusters.


Assuntos
Sinalização do Cálcio/fisiologia , Cálcio/metabolismo , Membrana Celular/fisiologia , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Ativação do Canal Iônico/fisiologia , Modelos Biológicos , Soluções Tampão , Simulação por Computador
10.
Phys Rev Lett ; 103(15): 154102, 2009 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-19905640

RESUMO

A free-boundary approach is applied to derive universal relationships between the excitability and the velocity and the shape of stabilized wave segments in a broad class of excitable media. In the earlier discovered low excitability limit wave segments approach critical fingers. We demonstrate the existence of a second universal limit (a motionless circular shaped spot) in highly excitable media. Analytically obtained asymptotic relationships and interpolation formula connecting both excitability limits are in good quantitative agreement with results from numerical simulations.


Assuntos
Simulação por Computador , Modelos Biológicos , Modelos Estatísticos , Modelos Teóricos
11.
Eur J Clin Microbiol Infect Dis ; 28(7): 821-4, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19194731

RESUMO

The purpose of this paper was to determine the population incidence and clinical features of Serratia sp. bacteremia in Canberra, Australia. Demographic and clinical data were collected prospectively for episodes of Serratia sp. bacteremia over a 10-year period, and was confined to Canberra residents using residential postal codes. Thirty-eight episodes of Serratia sp. bacteremia occurred, with a yearly incidence of 1.03 per 100,000 population. The majority of episodes occurred in males (68%). The respiratory tract was the most common focus of infection (21%). Twenty-nine percent of episodes were community-associated. A further 18% of episodes had their onset in the community but were healthcare-associated. The 7-day and 6-month mortality rates were 5 and 37%, respectively. Antibiotic resistance to gentamicin (3%) and ciprofloxacin (0%) was low. Serratia sp. bacteremia is more common than generally appreciated, with a large proportion (47%) of episodes having their onset in the community.


Assuntos
Bacteriemia/epidemiologia , Infecções por Serratia/epidemiologia , Serratia/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Austrália/epidemiologia , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Criança , Infecções Comunitárias Adquiridas/epidemiologia , Infecções Comunitárias Adquiridas/microbiologia , Infecções Comunitárias Adquiridas/mortalidade , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Infecção Hospitalar/mortalidade , Farmacorresistência Bacteriana , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Infecções por Serratia/mortalidade , Adulto Jovem
13.
Curr Biol ; 8(4): 223-6, 1998 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-9501984

RESUMO

The type I interferons--interferon-alpha (IFN-alpha) and interferon-beta (IFN-beta)--are critical for protection against viruses during the acute stage of viral infection [1,2]. Furthermore, type I interferons have been implicated as important mediators in the regulation of lymphocyte development [3], immune responses [4,5] and the maintenance of immunological memory of cytotoxic T cells [6,7]. The different IFN-alpha subtypes are encoded by 12 genes in the mouse [8] whereas IFN-beta is encoded by only one gene [9]. IFN-alpha and IFN-beta have a high degree of sequence homology and are thought to interact with the same surface receptor on target cells [10,11]. As an approach to analysing the different biological functions of IFN-alpha and IFN-beta, we have generated a mouse strain with an inactivated IFN-beta gene. We report here that embryonic fibroblasts from such mice produce neither IFN-beta nor IFN-alpha upon Sendal virus infection, whereas the production of IFN-alpha by leukocytes from the same strain of mice is intact. IFN-alpha production in embryonic fibroblasts from IFN-beta-/- mice could be rescued by 'priming' the cells using exogenous IFN-beta. These results imply a unique role for IFN-beta in the induction of type I interferons in peripheral tissues.


Assuntos
Embrião de Mamíferos/metabolismo , Interferon-alfa/biossíntese , Interferon beta/fisiologia , Animais , Embrião de Mamíferos/citologia , Embrião de Mamíferos/virologia , Fibroblastos/metabolismo , Fibroblastos/virologia , Interferon beta/genética , Camundongos , Mutagênese , Respirovirus/fisiologia
14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 75(6 Pt 1): 062101, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17677309

RESUMO

We consider the transport of overdamped particles in a two-dimensional periodic velocity field. This field possesses extended lines of fixed points where the deterministic motion stops. Additive noise makes the lines penetrable and results in an oscillatory motion along tori. We characterize the stochastic motion by the probability distribution density, the stationary mean velocity, and the mean times of escape from bounded domains. For intermediate noise intensities, the fluctuations enhance the transport of the particles compared to the deterministic case. A fast dichotomic modulation of asymmetry enhances fluxes.

15.
Psychoneuroendocrinology ; 31(1): 80-91, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16125866

RESUMO

Familial neurohypophysial diabetes insipidus (FNDI) is caused by a defect in vasopressin synthesis and release as a result of a heterozygous mutation in the gene for the vasopressin prohormone. The predominant characteristic of FNDI is excessive thirst and urine production. However, vasopressin not only has peripheral endocrine effects, but also regulates numerous brain functions. We investigated whether central functions are affected in FNDI, by studying neuropsychological functioning of 23 affected members (15 males, 8 females) of a large family carrying a T/G transition mutation at nucleotide 2110 (codon 116) of the vasopressin prohormone gene (Cys116Gly). The relatively large number of family members with FNDI made it possible to compare cognitive and other CNS effects in these subjects with those of family members without FNDI. Thirty-seven adult volunteers (20 males, 17 females) from the same family and 11 non-family members (2 males, 9 females) from northern part of The Netherlands were tested. The mean age of the subjects was 35+/-12 years. Of the 63 quantified neuropsychological parameters few were statistically different between the subjects with FDNI and control subjects. Memory retrieval processes and sustained attention were worse in the subjects with FDNI. Moreover, these individuals reported significantly fewer symptoms of agoraphobia and miscellaneous symptoms, and had significantly lower scores on a scale measuring anger. The performance of FNDI subjects on an auditory verbal learning test (the 15-word test learning trial) was worse, but not significantly so, than that of the subjects without FDNI. There were subjective complaints of forgetfulness and slow recalls and those were observed in daily life by non-affected family members. These moderate differences in neuropsychological performance indicate that in human FNDI parvocellular vasopressin systems that supply the brain may be less affected or give no such serious disabilities, than the magnocellular hypothalamo-neurohypophysial system that provides vasopressin for endocrine regulation of water homeostasis.


Assuntos
Sistema Nervoso Central/fisiopatologia , Diabetes Insípido Neurogênico/fisiopatologia , Diabetes Insípido Neurogênico/psicologia , Neuro-Hipófise/fisiopatologia , Adulto , Diabetes Insípido Neurogênico/genética , Família , Feminino , Humanos , Inteligência/fisiologia , Masculino , Memória/fisiologia , Pessoa de Meia-Idade , Motivação , Mutação/genética , Mutação/fisiologia , Testes Neuropsicológicos , Linhagem , Desempenho Psicomotor/fisiologia , Sede/fisiologia , Micção/fisiologia , Aprendizagem Verbal/fisiologia
16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 74(4 Pt 2): 046215, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17155161

RESUMO

Depending on the parameters of two-dimensional excitable or oscillatory media rigidly rotating or meandering spiral waves are observed. The transition from rigid rotation to meandering motion occurs via a supercritical Hopf bifurcation. To stabilize rigid rotation in a parameter range beyond the Hopf bifurcation, we propose and successfully apply a proportional control algorithm as well as time delay autosynchronization. Both control methods are noninvasive. This allows for determination of the parameters of unstable rigid rotation of spiral waves either for a model or an experimental system. Using the Oregonator model for the light-sensitive Belousov-Zhabotinsky reaction as a representative example we show that quite naturally some latency time appears in the control loop, and propose an efficient method to overcome its destabilizing influence.

17.
Phys Rev E Stat Nonlin Soft Matter Phys ; 74(1 Pt 2): 016214, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16907184

RESUMO

We show that characteristic features of noise-induced spatiotemporal patterns in excitable media can be effectively controlled by applying delayed feedback. Actually, by variation of the time delay and of the strength of the feedback one can deliberately change both spatial and temporal coherence, as well as adjust the characteristic time scales.

18.
Phys Rev E Stat Nonlin Soft Matter Phys ; 73(5 Pt 2): 056209, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16803028

RESUMO

We investigate Turing pattern formation in the presence of additive dichotomous fluctuations in the context of an extended system with diffusive coupling and FitzHugh-Nagumo kinetics. The fluctuations vary in space and/or time. Depending on the realization of the dichotomous switching the system is, at a given time (for spatial disorder at a given position) in one of two possible excitable dynamical regimes. Each of the two excitable dynamics for itself does not support pattern formation. With proper dichotomous fluctuations, however, the homogeneous steady state is destabilized via a Turing instability. We investigate the influence of different switching rates (different correlation length of the spatial disorder) on pattern formation. We find three distinct mechanisms: For slow switching existing boundaries become unstable, for high rates the system exhibits "effective bistability" which allows for a Turing instability. For medium rates the fluctuations create spatial structures via a new mechanism where the influence of the fluctuations is twofold. First they produce local inhomogeneities, which then grow (again caused by fluctuations) until the whole space is covered. Utilizing a nonlinear map approach we show bistability of a period-one and a period-two orbit being associated with the steady homogeneous and the Turing pattern state, respectively. Finally, for purely static dichotomous disorder we find destabilization of homogeneous steady states for finite nonzero correlation length of the disorder resulting again in Turing patterns.

19.
Cancer Res ; 54(7): 1746-52, 1994 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-7511050

RESUMO

CD38 is a leukocyte differentiation antigen that has been thought to be a phenotypic marker of different subpopulations of T- and B-lymphocytes. In myeloid cells, CD38 is expressed during early stages of differentiation. Virtually no information is available on regulation and functions of CD38. Recently we reported that all-trans-retinoic acid (ATRA) is a potent and highly specific inducer of CD38 expression in human promyelocytic leukemia cells. Here we report that ATRA-induced expression of CD38 antigen in myeloid cells is mediated through retinoic acid-alpha receptor (RAR alpha). ATRA failed to induce CD38 expression in a mutant subclone of the HL-60 myeloid leukemia cell line (designated HL-60R) that is relatively resistant to ATRA-induced granulocytic differentiation. Retroviral vector-mediated transduction of RA receptor (RAR alpha) into this HL-60R subclone completely restored the sensitivity of these cells to ATRA in terms of their ability to express CD38. In contrast, CD38 expression was not inducible by ATRA in HL-60R cells, transfected with a functional RAR beta, RAR gamma, or RXR alpha receptor. Induction of CD38 in acute promyelocytic and acute myeloblastic leukemia cells was independent of ATRA-induced cytodifferentiation. Following culture with ATRA, increased CD38 protein levels were also observed in normal CD34+ bone marrow cells, but not on normal circulating granulocytes. From these results, we conclude that CD38 is ATRA inducible in myeloid leukemia cells and normal CD34+ bone marrow cells. This effect is independent of differentiation and is mediated by RAR alpha in HL-60 cells, suggesting a similar role for RAR alpha in CD38 expression in other hematopoietic cells.


Assuntos
Antígenos CD/biossíntese , Antígenos de Diferenciação/biossíntese , Receptores do Ácido Retinoico/fisiologia , Tretinoína/farmacologia , ADP-Ribosil Ciclase , ADP-Ribosil Ciclase 1 , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Medula Óssea/patologia , Diferenciação Celular , Linhagem Celular , Células Clonais , Relação Dose-Resposta a Droga , Resistência a Medicamentos , Citometria de Fluxo , Expressão Gênica/efeitos dos fármacos , Fator Estimulador de Colônias de Granulócitos/farmacologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Granulócitos/citologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Células-Tronco Hematopoéticas/metabolismo , Humanos , Interferon gama/farmacologia , Cinética , Leucemia Mielogênica Crônica BCR-ABL Positiva , Leucemia Promielocítica Aguda , Glicoproteínas de Membrana , Receptores do Ácido Retinoico/biossíntese , Receptores do Ácido Retinoico/efeitos dos fármacos , Proteínas Recombinantes/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Transfecção , Células Tumorais Cultivadas
20.
Oncogene ; 20(35): 4877-83, 2001 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-11521199

RESUMO

TFIIIB, TFIIIC2, and PTF/SNAPC are heteromultimeric general transcription factors (GTFs) needed for expression of genes encoding small cytoplasmic (scRNAs) and small nuclear RNAs (snRNAs). Their activity is stimulated by viral oncogenes, such as SV40 large T antigen and Adenovirus E1A, and is repressed by specific transcription factors (STFs) acting as anti-oncogenes, such as p53 and pRb. GTFs role as final targets of critical signal transduction pathways, that control cell proliferation and differentiation, and their involvement in gene expression regulation suggest that the genes encoding them are potential proto-oncogenes or anti-oncogenes or may be otherwise involved in the pathogenesis of inherited genetic diseases. To test our hypothesis through the positional candidate gene approach, we have determined the physical localization in the human genome of the 11 genes, encoding the subunits of these GTFs, and of three genes for proteins associated with TFIIIB (GTF3BAPs). Our data, obtained by chromosomal in situ hybridization, radiation hybrids and somatic cell hybrids analysis, demonstrate that these genes are present in the human genome as single copy sequences and that some cluster to the same cytogenetic band, alone or in combination with class II GTFs. Intriguingly, some of them are localized within chromosomal regions where recurrent, cytogenetically detectable mutations are seen in specific neoplasias, such as neuroblastoma, uterine leyomioma, mucoepidermoid carcinoma of the salivary glands and hemangiopericytoma, or where mutations causing inherited genetic diseases map, such as Peutz-Jeghers syndrome. Their molecular function and genomic position make these GTF genes interesting candidates for causal involvement in oncogenesis or in the pathogenesis of inherited genetic diseases.


Assuntos
Predisposição Genética para Doença , Genoma Humano , Neoplasias/etiologia , Fatores de Transcrição TFIII/genética , Fatores de Transcrição/genética , Mapeamento Cromossômico , Humanos , Neoplasias/genética , Fator de Transcrição TFIIIB
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA