Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 288
Filtrar
1.
Osteoporos Int ; 35(3): 495-503, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37938405

RESUMO

INTRODUCTION: While the United States Preventative Services Task Force recommends osteoporosis screening for women 65 years and older, there is no definitive recommendation for routine osteoporosis screening in men. The purpose of this study was to determine the age at which the odds of fragility fractures (FFx) increase in men to help guide future policy discussions evaluating an optimal screening strategy in this population. METHODS: Men older than 49 years were identified in the PearlDiver Patient Records Database. Patients were excluded if they had a prior fragility fracture, if they were at high risk for osteoporosis due to comorbidities, or if they carried a diagnosis of and/or were on treatment for osteoporosis. The prevalence of FFx was trended for each age group. A stratum-specific likelihood ratio (SSLR) analysis was conducted to identify data-driven strata that maximize the incremental FFx risk by age for men. Logistic regression analyses controlling for potential confounders were conducted to test these identified strata. RESULTS: The incidence of FFx started to increase after the age of 64 years for men. Further, the identified data-driven age strata associated with a significant and incremental difference in fragility fractures were the following: 50-64, 65-69, 70-72, 73-75, 76-78, 79-80, and 81+. When compared to the youngest age stratum (50-64 years), multivariable regression showed the risk of fragility fracture incrementally increased starting in those aged 70-72 (RR, 1.31; 95% CI. 1.21-1.46; p < 0.001) with the highest risk in those aged 81+ (RR, 5.35; 95% CI, 5.10-5.62; p < 0.001). CONCLUSION: In men without a pre-existing history of osteoporosis, the risk of fragility fractures starts to increase after the age of 70. Further work building upon these data may help to identify a specific age at which routine bone health screening in males can help to minimize fractures and their associated morbidity and mortality.


Assuntos
Fraturas Ósseas , Osteoporose , Fraturas por Osteoporose , Masculino , Humanos , Feminino , Fraturas Ósseas/epidemiologia , Osteoporose/complicações , Osteoporose/epidemiologia , Envelhecimento , Osso e Ossos , Incidência , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/complicações , Fatores de Risco
2.
Clin Genet ; 93(5): 1030-1038, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29251763

RESUMO

Due to small numbers of reported patients with pathogenic variants in single genes, the phenotypic spectrum associated with genes causing neurodevelopmental disorders such as intellectual disability (ID) and autism spectrum disorder is expanding. Among these genes is KLF7 (Krüppel-like factor 7), which is located at 2q33.3 and has been implicated in several developmental processes. KLF7 has been proposed to be a candidate gene for the phenotype of autism features seen in patients with a 2q33.3q34 deletion. Herein, we report 4 unrelated individuals with de novo KLF7 missense variants who share similar clinical features of developmental delay/ID, hypotonia, feeding/swallowing issues, psychiatric features and neuromuscular symptoms, and add to the knowledge about the phenotypic spectrum associated with KLF7 haploinsufficiency.


Assuntos
Transtorno do Espectro Autista/genética , Deficiências do Desenvolvimento/genética , Deficiência Intelectual/genética , Fatores de Transcrição Kruppel-Like/genética , Adolescente , Transtorno do Espectro Autista/patologia , Transtorno do Espectro Autista/psicologia , Criança , Pré-Escolar , Deficiências do Desenvolvimento/patologia , Deficiências do Desenvolvimento/psicologia , Feminino , Predisposição Genética para Doença , Haploinsuficiência/genética , Humanos , Deficiência Intelectual/patologia , Deficiência Intelectual/psicologia , Masculino , Mutação de Sentido Incorreto/genética , Sequenciamento do Exoma
3.
Clin Genet ; 93(4): 752-761, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28881385

RESUMO

Diagnostic exome sequencing (DES) has aided delineation of the phenotypic spectrum of rare genetic etiologies of intellectual disability (ID). A SET domain containing 5 gene (SETD5) phenotype of ID and dysmorphic features has been previously described in relation to patients with 3p25.3 deletions and in a few individuals with de novo sequence alterations. Herein, we present additional patients with pathogenic SETD5 sequence alterations. The majority of patients in this cohort and previously reported have developmental delay, behavioral/psychiatric issues, and variable hand and skeletal abnormalities. We also present an apparently unaffected carrier mother of an affected individual and a carrier mother with normal intelligence and affected twin sons. We suggest that the phenotype of SETD5 is more complex and variable than previously presented. Therefore, many features and presentations need to be considered when evaluating a patient for SETD5 alterations through DES.


Assuntos
Transtornos Dismórficos Corporais/genética , Deficiências do Desenvolvimento/genética , Deficiência Intelectual/genética , Metiltransferases/genética , Adolescente , Adulto , Transtornos Dismórficos Corporais/diagnóstico , Transtornos Dismórficos Corporais/fisiopatologia , Criança , Pré-Escolar , Deleção Cromossômica , Cromossomos Humanos Par 3/genética , Deficiências do Desenvolvimento/diagnóstico , Deficiências do Desenvolvimento/fisiopatologia , Feminino , Humanos , Lactente , Deficiência Intelectual/diagnóstico , Deficiência Intelectual/fisiopatologia , Masculino , Pessoa de Meia-Idade , Mutação/genética , Penetrância , Fenótipo , Sequenciamento do Exoma , Adulto Jovem
4.
Clin Genet ; 91(5): 697-707, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27598823

RESUMO

Identification of rare genetic variants in patients with intellectual disability (ID) has been greatly accelerated by advances in next generation sequencing technologies. However, due to small numbers of patients, the complete phenotypic spectrum associated with pathogenic variants in single genes is still emerging. Among these genes is ZBTB18 (ZNF238), which is deleted in patients with 1q43q44 microdeletions who typically present with ID, microcephaly, corpus callosum (CC) abnormalities, and seizures. Here we provide additional evidence for haploinsufficiency or dysfunction of the ZBTB18 gene as the cause of ID in five unrelated patients with variable syndromic features who underwent whole exome sequencing revealing separate de novo pathogenic or likely pathogenic variants in ZBTB18 (two missense alterations and three truncating alterations). The neuroimaging findings in our cohort (CC hypoplasia seen in 4/4 of our patients who underwent MRI) lend further support for ZBTB18 as a critical gene for CC abnormalities. A similar phenotype of microcephaly, CC agenesis, and cerebellar vermis hypoplasia has been reported in mice with central nervous system-specific knockout of Zbtb18. Our five patients, in addition to the previously described cases of de novo ZBTB18 variants, add to knowledge about the phenotypic spectrum associated with ZBTB18 haploinsufficiency/dysfunction.


Assuntos
Deficiência Intelectual/genética , Mutação , Proteínas Repressoras/genética , Anormalidades Múltiplas/genética , Adulto , Criança , Pré-Escolar , Deleção Cromossômica , Cromossomos Humanos Par 1/genética , Exoma , Feminino , Haploinsuficiência , Humanos , Imageamento por Ressonância Magnética , Masculino , Microcefalia/genética , Mutação de Sentido Incorreto , Gravidez
5.
Clin Genet ; 88(5): 425-30, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25534182

RESUMO

Neurofibromatosis type 1 (NF1) carries a significant psychosocial burden for affected individuals. The objective of this study was to measure the prevalence of depressive symptoms among a large sample of adults with NF1 and to quantify the impact of depressive symptoms on quality of life (QoL). This cross-sectional study used an Internet-based questionnaire to collect data from 498 adults who self-reported as having NF1. Using the Center for Epidemiologic Studies Depression (CESD) scale, 55% of all participants (61% of females and 43% of males) scored above 16, indicating a high likelihood of clinical depression. In a multivariate regression model controlling for demographics and potential confounders, depressive symptoms accounted for 32% of the variance in QoL as measured by the Quality of Life Index. This study is the largest to date and found the highest prevalence of depression compared to prior studies. Our data provide more compelling evidence that individuals with NF1 are at increased risk for psychiatric morbidity and suggest that this population should be routinely screened for depression. Because depression was found to be strongly associated with QoL and accounted for nearly one-third of the variance in QoL, it is likely that effectively treating depression may significantly enhance QoL for individuals with NF1.


Assuntos
Depressão/epidemiologia , Neurofibromatose 1/psicologia , Qualidade de Vida , Adulto , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Autorrelato , Fatores Sexuais , Inquéritos e Questionários , Adulto Jovem
6.
Oecologia ; 174(4): 1359-66, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24402130

RESUMO

Plant species composition is changing across many landscapes, but it is unclear how these changes affect habitat quality for animals. We used functional diversity and community-weighted mean (CWM) trait values for four plant traits (litter N, P, lignin and soluble phenolics) to explore how changes in plant species composition may affect larval amphibians in a simplified aquatic ecosystem. We predicted that increased functional diversity would improve amphibian performance (survivorship, developmental rate, and size). We also predicted that increases in CWM N and P would improve amphibian performance, while increases in CWM lignin and soluble phenolics would have negative effects on amphibian performance. We did not detect an effect of functional diversity; instead, CWM litter N and soluble phenolics were useful predictors of amphibian performance. We demonstrate that quantifying the CWM of ecologically relevant traits represents a powerful approach for predicting how changes in plant species composition can affect aquatic communities.


Assuntos
Ecossistema , Plantas/química , Ranidae/crescimento & desenvolvimento , Animais , Larva , Lignina/química , Nitrogênio/química , Fenóis/química , Fósforo/química
7.
Br J Ophthalmol ; 92(10): 1387-92, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18621791

RESUMO

BACKGROUND: Bimatoprost 0.03% has been shown to consistently reduce mean intraocular pressure (IOP) more than timolol 0.5% over 2 years. To further evaluate long-term safety and efficacy, once-daily bimatoprost 0.03% was compared with timolol 0.5% twice daily through year 4. METHODS: In this multicentre, double-masked, randomised, controlled trial, glaucoma and ocular hypertension patients (n = 152) who completed phase III bimatoprost trials through month 36 were enrolled in a study extension through month 48. Patients randomised to bimatoprost once daily (n = 78) or timolol twice daily (n = 35) continued on the same regimen for a fourth year. Patients randomised to bimatoprost twice daily had been switched to bimatoprost once daily dosing at month 24 (bimatoprost twice daily/once daily treatment group), and continued with once daily dosing through month 48 (n = 39). IOP was measured at 08:00 and 10:00 at months 39, 42, 45 and 48. Safety measures included adverse events, biomicroscopy, ophthalmoscopy, visual acuity and visual field. RESULTS: Baseline IOP was comparable among groups. During year 4, mean IOP reductions from baseline were 7.0 to 8.1 mm Hg with bimatoprost once daily and 6.5 to 7.9 mm Hg with bimatoprost twice daily/once daily, significantly greater than with timolol twice daily (3.8 to 5.8 mm Hg, p< or =0.035) at all measurements. Over 4 years, the mean IOP reduction from baseline at 08:00 and 10:00 was 1.9 to 3.9 mm Hg (35% to 100%) greater with bimatoprost once daily than with timolol (p< or =0.013). Low IOPs were achieved by more bimatoprost than timolol patients (p< or =0.042). No safety concerns developed during long-term bimatoprost treatment; two patients in the timolol treatment group discontinued after month 36 because of adverse events. The most common treatment-related adverse event in the bimatoprost treatment groups was conjunctival hyperaemia. CONCLUSION: Bimatoprost once daily provided sustained IOP lowering greater than timolol twice daily and was well tolerated over long-term use.


Assuntos
Amidas/administração & dosagem , Cloprostenol/análogos & derivados , Glaucoma/tratamento farmacológico , Pressão Intraocular/efeitos dos fármacos , Hipertensão Ocular/tratamento farmacológico , Amidas/efeitos adversos , Análise de Variância , Bimatoprost , Cloprostenol/administração & dosagem , Cloprostenol/efeitos adversos , Doenças da Túnica Conjuntiva/induzido quimicamente , Método Duplo-Cego , Esquema de Medicação , Feminino , Glaucoma/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Hipertensão Ocular/fisiopatologia , Timolol/uso terapêutico , Resultado do Tratamento , Acuidade Visual/fisiologia
9.
Int J Obes Relat Metab Disord ; 28(3): 384-90, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14767494

RESUMO

OBJECTIVE: The objectives were two-fold: (1) determine whether the use of hydralazine as antihypertensive therapy during obesity development exacerbated obesity-related cardioacceleration and hormonal abnormalities; (2) determine whether the absence of hypertension in obesity attenuated obesity-related abnormalities in hemodynamics, cardiac hypertrophy, and hormonal profile. DESIGN: Female New Zealand White rabbits were divided into lean control (n=12), lean hydralazine-treated (n=9), obese control (n=11), and obese hydralazine-treated (n=8) groups. Pretreatment mean blood pressure (BP) and heart rate (HR) were determined using telemetry. Pretreatment BP was maintained during 12 weeks of obesity development using hydralazine. MEASUREMENTS: Chronically measured BP and HR; plasma/blood volume; wet and dry ventricular weights; body fat/water; and hormonal profile (plasma renin activity, aldosterone, cortisol, atrial natriuretic peptide, adrenaline, and noradrenaline). RESULTS: Hydralazine treatment in obese animals attenuated obesity-related renin-angiotensin system (RAS) activation. In contrast, RAS was activated in lean hydralazine, as indicated by increased plasma aldosterone. The absence of hypertension in obese hydralazine did not result in attenuation of cardioacceleration, cardiac hypertrophy, or intravascular volumes. CONCLUSIONS: Hydralazine treatment in obese rabbits did not exacerbate obesity-related cardiovascular and hormonal alterations. Cardioacceleration and cardiac hypertrophy persisted in obese hydralazine despite BP control, suggesting hypertension-independent effects of obesity on these variables. Hydralazine's effects on RAS activation differed in lean and obese rabbits, suggesting that the systemic effects of hydralazine as a control therapy in evaluation of antihypertensive medications may differ depending on the underlying pathology.


Assuntos
Anti-Hipertensivos/uso terapêutico , Hidralazina/uso terapêutico , Hipertensão/tratamento farmacológico , Obesidade/complicações , Animais , Anti-Hipertensivos/toxicidade , Biometria , Pressão Sanguínea/efeitos dos fármacos , Cardiomegalia/etiologia , Feminino , Frequência Cardíaca/efeitos dos fármacos , Hormônios/sangue , Hidralazina/toxicidade , Hipertensão/etiologia , Obesidade/sangue , Obesidade/fisiopatologia , Coelhos , Sistema Renina-Angiotensina/efeitos dos fármacos
10.
Heart ; 90(1): 87-91, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14676253

RESUMO

BACKGROUND: Interventional magnetic resonance imaging (iMRI) has the potential for guiding interventional cardiac procedures in real time. OBJECTIVES: To test the feasibility of iMRI guided gene and cell transfer to the heart and to monitor myocardial remodelling after myocardial infarction in a rat model. METHODS: The MRI contrast agent GdDTPA, together with either Evans blue dye, or a recombinant adenovirus encoding the LacZ gene, or primary fibroblasts tagged by BrdU, were injected into the myocardium of rats under iMRI guidance. Rats were killed seven days after the injection and the hearts sectioned to identify the blue dye, LacZ expression, or fibroblast presence, respectively. In a parallel study, left ventricular area was measured before and after myocardial infarction and in sham operated rats by T1 weighted MRI and by echocardiography. RESULTS: Location of GdDTPA enhancement observed with iMRI at the time of injection was correlated with Evans blue stain, beta-gal expression, and the primary fibroblast location in histological studies. iMRI and echocardiography measured a comparable increase in left ventricular area at seven and 30 days after myocardial infarction. A good correlation was found between the iMRI and echocardiographic assessment of left ventricular area (r = 0.70; p < 0.0001) and change in left ventricular area with time (r = 0.75; p < 0.0001). CONCLUSIONS: The results show the feasibility and efficiency of iMRI guided intramyocardial injections, and the ability to monitor heart remodelling using iMRI. Genes, proteins, or cells for tissue engineering could be injected accurately into the myocardial scar under iMRI guidance.


Assuntos
Técnicas de Transferência de Genes , Terapia Genética/métodos , Angiografia por Ressonância Magnética/métodos , Infarto do Miocárdio/terapia , Adenoviridae/genética , Animais , Corantes , Meios de Contraste , Ecocardiografia , Azul Evans , Estudos de Viabilidade , Fibroblastos/transplante , Gadolínio DTPA , Vetores Genéticos , Injeções , Óperon Lac/genética , Ratos , Ratos Sprague-Dawley , Remodelação Ventricular/genética
11.
Anim Learn Behav ; 30(3): 261-74, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12391792

RESUMO

Rats were exposed to three-trial series consisting of reinforced (R) trials and one nonreinforced (N) trial in a fixed order, RRN and RNR (Experiments 1 and 2) or NRR and RRN (Experiment 3), on extended visually distinct runways in a T-maze. When initially presented with the same sequence on each series in a session (separate presentations) with the same runway on all trials within a series (Experiments 1 and 3), all the rats developed slower running speeds on N than on R trials. When a runway was sometimes changed between the first and next two trials during separate presentations training (Experiment 2) or both sequences were later intermixed within each session in each experiment, only rats exposed to each sequence on a specific runway maintained these serial running patterns. Rats displayed serial running patterns on a test RNN sequence similar to that on the RNR sequence (Experiment 2), as would be predicted by an intertrial association model of serial pattern learning (Capaldi & Molina, 1979), but responded on test RRR and NRN sequences (Experiment 3) as would be predicted by an ordinal-trial-tag/intratrial association model (Burns, Wiley, & Payne, 1986). Results from test series of free-choice trials in Experiments 1 and 2 failed to support a prediction of the intratrial association model that these rats would integrate RRN and RNR sequences. Rather than always selecting a baited runway on both the second and the third free-choice trials, the rats only selected a baited runway on the third trial on the basis of their choice on the second trial, as would be predicted by the intertrial association model. Only after experiencing all possible outcome sequences during forced-choice training in Experiment 3 did these rats predominantly select a baited runway on every free-choice trial.


Assuntos
Aprendizagem por Discriminação , Aprendizagem em Labirinto , Animais , Comportamento de Escolha , Masculino , Ratos , Ratos Long-Evans
13.
J Cataract Refract Surg ; 27(11): 1732-40, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11709244

RESUMO

PURPOSE: To determine the efficacy and safety of surgical implantation of prosthetic iris devices in patients with anatomic or functional iris deficiencies. SETTING: Cincinnati Eye Institute, Cincinnati, Ohio, USA. METHODS: Twenty-five patients were enrolled in an interventional prospective noncomparative case series. Twenty-eight eyes had prosthetic iris diaphragm implantation for traumatic iris defects, congenital aniridia or iris coloboma, herpetic iris atrophy, surgical iris loss, or ocular albinism. Prosthetic iris implantation was performed with phacoemulsification and intraocular lens (IOL) implantation in 20 eyes, secondary IOL implantation in 6 eyes, and IOL exchange in 1 eye. A single pseudophakic eye with disabling glare secondary to traumatic aniridia had secondary prosthetic iris implantation alone. The surgical ease of insertion, intraoperative and postoperative complications, postoperative anatomic results, visual acuity, and subjective glare reduction were evaluated. RESULTS: Patients were followed postoperatively for a mean of 10.2 months (range 1.4 to 25.7 months). All eyes achieved the desired anatomic result. Visual acuity was improved in 22 of 28 eyes (79%), unchanged in 5 eyes, and worsened by a single line in 1 eye. Patients were surveyed postoperatively to determine the change in glare disability. The severity of glare disability was subjectively improved in 23 of 24 patients (96%) who responded to the survey. Intraoperative complications included 3 fractured implants as well as an incomplete or torn capsulorhexis in 3 eyes. Postoperative complications included transient hypotony in 2 eyes, mild persistent inflammation in 1 eye, and macular edema followed by a retinal detachment in 1 eye with recent severe trauma. CONCLUSIONS: Implantation of prosthetic iris devices improved postoperative outcomes by reducing glare disability and, in selected cases, by correcting aphakia. Although operating on traumatized, congenitally aniridic, or uveitic eyes presents special challenges, implantation of prosthetic iris devices appears to be a safe and effective method for reducing the ubiquitous glare in patients with iris deficiency.


Assuntos
Aniridia/cirurgia , Coloboma/cirurgia , Traumatismos Oculares/cirurgia , Iris/cirurgia , Próteses e Implantes , Implantação de Prótese , Adulto , Idoso , Feminino , Ofuscação , Humanos , Complicações Intraoperatórias , Iris/anormalidades , Iris/lesões , Doenças da Íris/cirurgia , Implante de Lente Intraocular , Masculino , Pessoa de Meia-Idade , Facoemulsificação , Complicações Pós-Operatórias , Estudos Prospectivos , Segurança , Acuidade Visual
14.
Cancer Res ; 61(20): 7536-43, 2001 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-11606391

RESUMO

Magnetic resonance spectroscopy (MRS) methods have provided valuable information on cancer cell metabolism. In this study, we characterized the 31P-MR spectra of breast cancer cell lines exhibiting differences in hormonal response, estrogen receptors (positive/negative), and metastatic potential. A correlation was made between the cytotoxic effect of antimitotic drugs and changes in cell metabolism pattern. Because most anticancer drugs are more effective on proliferating cells, our study attempted to elucidate the metabolic profile and specific metabolic changes associated with the effect of anticancer drugs on proliferating breast cancer cell lines. Accordingly, for the 31P-MRS experiments, cells were embedded in Matrigel to preserve their proliferation profile and ability to absorb drugs. The MRS studies of untreated cells indicated that the levels of phosphodiesters and uridine diphosphosugar metabolites were significantly higher in estrogen receptor-positive and low metastatic potential cell lines. 31P-MRS observations revealed a correlation between the mode of action of anticancer drugs and the observed changes in cell metabolic profiles. When cells were treated with antimicrotubule drugs (paclitaxel, vincristine, colchicine, nocodazole), but not with methotrexate and doxorubicin, a profound elevation of intracellular glycerophosphorylcholine (GPC) was recorded that was not associated with changes in phospholipid composition of cell membrane. Remarkably, the rate of elevation of intracellular GPC was much faster in cell population synchronized at G2-M compared with the unsynchronized cells. The steady-state level of GPC for paclitaxel-treated cells was reached after approximately 4 h for synchronized cells and after approximately 24 h (approximate duration of one cell cycle) for the unsynchronized ones. These observations may indicate a correlation between microtubule status and cellular phospholipid metabolism. This study demonstrates that 31P-MRS may have diagnostic value for treatment decisions of breast cancer and reveals new aspects of the mechanism of action of antimicrotubule drugs.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Fosfolipídeos/metabolismo , Antineoplásicos/farmacocinética , Neoplasias da Mama/patologia , Ciclo Celular/fisiologia , Divisão Celular/fisiologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Colágeno , Doxorrubicina/farmacologia , Combinação de Medicamentos , Fase G2/fisiologia , Laminina , Metotrexato/farmacologia , Mitose/fisiologia , Nocodazol/farmacologia , Ressonância Magnética Nuclear Biomolecular/métodos , Paclitaxel/farmacocinética , Paclitaxel/farmacologia , Fosfatidilcolinas/metabolismo , Fósforo , Proteoglicanas , Células Tumorais Cultivadas , Vincristina/farmacologia
16.
Biophys J ; 81(2): 994-1005, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11463641

RESUMO

The effects of binding of myristoylated ADP ribosylation factor 6 (myr-ARF6), an activator of phospholipase D (PLD), to a model membrane were investigated using an electron spin resonance (ESR) labeling technique. Initial studies were conducted in vesicles composed of 1-palmitoyl-2-oleoyl phosphatidylethanolamine, dipalmitoylphosphatidylcholine, phosphatidylinositol 4,5-biphosphate (PIP(2)), and cholesterol. Recombinant ARF6 binding significantly enhances defects in both the headgroup and acyl-chain regions of the membrane, which are revealed by the emergence of sharp components in the spectra from a headgroup label, 1,2-dipalmitoylphosphatidyl-2,2,6,6-tetramethyl-1-piperidinyloxy-choline (DPPTC), and a chain label, 10PC, after myr-ARF6 binding. Binding of non-myristoylated ARF6 (non-ARF6) shows markedly reduced effects. Interestingly, no change in spectra from DPPTC was observed upon myr-ARF6 binding when PIP(2) in the vesicles was replaced by other negatively charged lipids, including phosphatidylinositol, phosphatidylserine, and phosphatidylglycerol, even when normalized for charge. The production of the sharp peak appears to be a specific event, because another GTP binding protein, CDC42, which binds PIP(2) and activates PLD, fails to induce changes in vesicle structure. These results suggest a previously unappreciated role for ARF in mediating a protein/lipid interaction that produces defects in lipid bilayers. This function may serve as an initial event in destabilizing membrane structure for subsequent membrane fusion or biogenesis of vesicles.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Bicamadas Lipídicas/química , Bicamadas Lipídicas/metabolismo , Lipossomos/química , Lipossomos/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fator 6 de Ribosilação do ADP , Humanos , Espectroscopia de Ressonância Magnética , Modelos Biológicos , Fosfatidilcolinas/metabolismo , Ligação Proteica , Marcadores de Spin
17.
Cancer Res ; 61(13): 4971-3, 2001 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-11431326

RESUMO

Convection-enhanced drug delivery (CEDD) is a novel approach to enhance the delivery of drugs directly into brain tumors. We have used diffusion-weighted MRI (DWMRI) to monitor the effects of intratumoral CEDD in three brain tumor patients treated with Taxol. Clear changes in the images and the water diffusion parameters were observed shortly after the initiation of treatment. Initially, a bright area corresponding to decreased diffusion appeared, followed by the appearance of a dark area of increased diffusion within the bright area. The time to appearance of the dark area varied among the patients, suggesting different response rates. In this work, we have demonstrated the feasibility of using DWMRI as a noninvasive tool to achieve unique early tissue characterization not attainable by other conventional imaging methods.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Neoplasias Encefálicas/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Glioma/tratamento farmacológico , Paclitaxel/administração & dosagem , Neoplasias Encefálicas/patologia , Convecção , Difusão , Glioma/patologia , Humanos , Imageamento por Ressonância Magnética/métodos , Monitorização Fisiológica/métodos , Recidiva Local de Neoplasia/tratamento farmacológico , Água/metabolismo
18.
Proc Natl Acad Sci U S A ; 98(13): 7152-7, 2001 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-11416200

RESUMO

Biological membranes contain an extraordinary diversity of lipids. Phospholipids function as major structural elements of cellular membranes, and analysis of changes in the highly heterogeneous mixtures of lipids found in eukaryotic cells is central to understanding the complex functions in which lipids participate. Phospholipase-catalyzed hydrolysis of phospholipids often follows cell surface receptor activation. Recently, we demonstrated that granule fusion is initiated by addition of exogenous, nonmammalian phospholipases to permeabilized mast cells. To pursue this finding, we use positive and negative mode Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS) to measure changes in the glycerophospholipid composition of total lipid extracts of intact and permeabilized RBL-2H3 (mucosal mast cell line) cells. The low energy of the electrospray ionization results in efficient production of molecular ions of phospholipids uncomplicated by further fragmentation, and changes were observed that eluded conventional detection methods. From these analyses we have spectrally resolved more than 130 glycerophospholipids and determined changes initiated by introduction of exogenous phospholipase C, phospholipase D, or phospholipase A2. These exogenous phospholipases have a preference for phosphatidylcholine with long polyunsaturated alkyl chains as substrates and, when added to permeabilized mast cells, produce multiple species of mono- and polyunsaturated diacylglycerols, phosphatidic acids, and lysophosphatidylcholines, respectively. The patterns of changes of these lipids provide an extraordinarily rich source of data for evaluating the effects of specific lipid species generated during cellular processes, such as exocytosis.


Assuntos
Degranulação Celular/fisiologia , Sarcoma de Mastócitos/fisiopatologia , Fosfolipídeos/metabolismo , Animais , Permeabilidade da Membrana Celular , Análise de Fourier , Espectrometria de Massas/métodos , Fosfatidilcolinas/metabolismo , Fosfolipase D/metabolismo , Fosfolipases A/metabolismo , Fosfolipases A2 , Fosfolipídeos/química , Ratos , Espectrometria de Massas por Ionização por Electrospray/métodos , Especificidade por Substrato , Células Tumorais Cultivadas , Fosfolipases Tipo C/metabolismo
19.
Biochemistry ; 40(22): 6589-97, 2001 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-11380253

RESUMO

Roles for glycerophospholipids in exocytosis have been proposed, but remain controversial. Phospholipases are stimulated following the activation of the high-affinity receptor for immunoglobulin E (IgE) in mast cells. To study the biochemical sequelae that lead to degranulation, broken cell systems were employed. We demonstrate that the addition of three distinct types of exogenous phospholipases (i.e., bcPLC, scPLD, and tfPLA(2)), all of which hydrolyze phosphatidylcholine (PC), trigger degranulation in permeabilized RBL-2H3 cells, a mucosal mast cell line. Production of bioactive lipids by these phospholipases promotes release of granule contents through the plasma membrane and acts downstream of PKC, PIP(2), and Rho subfamily GTPases in regulated secretion. These exogenous phospholipase-induced degranulation pathways circumvent specific factors activated following stimulation of the IgE receptor as well as in ATP- and GTP-dependent intracellular pathways. Taken together, these results suggest that regulated secretion may be achieved in vitro in the absence of cytosolic factors via phospholipase activation and that products of PC hydrolysis can promote exocytosis in mast cells.


Assuntos
Proteínas de Bactérias , Mastócitos/enzimologia , Mastócitos/metabolismo , Fosfolipase D/metabolismo , Fosfolipases Tipo C/metabolismo , Animais , Bacillus cereus/enzimologia , Toxinas Bacterianas/farmacologia , Transporte Biológico , Degranulação Celular/efeitos dos fármacos , Membrana Celular/imunologia , Membrana Celular/metabolismo , Clostridioides difficile/fisiologia , Grânulos Citoplasmáticos/enzimologia , Grânulos Citoplasmáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Imuno-Histoquímica , Leucemia Basofílica Aguda/enzimologia , Leucemia Basofílica Aguda/metabolismo , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Naftalenos/farmacologia , Neomicina/farmacologia , Fosfolipase D/antagonistas & inibidores , Ratos , Streptomyces/enzimologia , Células Tumorais Cultivadas/enzimologia , Células Tumorais Cultivadas/metabolismo , Fosfolipases Tipo C/antagonistas & inibidores
20.
Arch Intern Med ; 161(7): 957-64, 2001 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-11295958

RESUMO

BACKGROUND: Adverse drug events (ADEs) are a major cause of morbidity and mortality, and even minor ADEs may adversely affect patients' compliance with treatment. Because most ADEs are dose-related phenomena, adjusting drug dosages to account for individual patients' needs and tolerances is fundamental to good therapeutics. OBJECTIVE: To determine whether the Physicians' Desk Reference (PDR), the leading source of drug information for physicians, provides the full range of effective drug doses, especially the lowest, least ADE-prone doses of medications, for physicians to consider in treating patients. METHODS: Review of dosage guidelines and dose-response information in the PDR. Comparison with dose-response data obtained from articles listed in MEDLINE from 1966 to 2000. RESULTS: For many types of medications, physicians are frequently advised to use the lowest effective doses of drugs, especially initially. Yet, effective low doses determined in prerelease studies or in postrelease work are often omitted from the PDR, even when they have been recommended by expert panels. CONCLUSIONS: Optimal therapeutics depends on the availability of comprehensive information. However, the PDR contains only the limited dose information from package inserts. Because the PDR was originally developed as a promotional device, there is no mechanism by which all clinically relevant dose-response data or important postrelease discoveries are regularly and rapidly incorporated into it. Thus, a gap exists in the availability of current and comprehensive dose information for physicians. This article provides information on lower, effective doses for 48 major medications, with an extensive reference list-a compilation of low-dose information not previously published, to our knowledge, in the medical literature. Physicians must have a readily accessible source of current and complete dose-response information to individualize drug therapy and minimize the risks of ADEs.


Assuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/normas , Serviços de Informação sobre Medicamentos/normas , Farmacopeias como Assunto/normas , Guias de Prática Clínica como Assunto/normas , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/efeitos adversos , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/efeitos adversos , Viés , Relação Dose-Resposta a Droga , Indústria Farmacêutica , Estrogênios Conjugados (USP)/administração & dosagem , Estrogênios Conjugados (USP)/efeitos adversos , Humanos , MEDLINE , Avaliação das Necessidades , Literatura de Revisão como Assunto
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA