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1.
Proc Natl Acad Sci U S A ; 121(12): e2316878121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38466851

RESUMO

Deep sea cold seeps are sites where hydrogen sulfide, methane, and other hydrocarbon-rich fluids vent from the ocean floor. They are an important component of Earth's carbon cycle in which subsurface hydrocarbons form the energy source for highly diverse benthic micro- and macro-fauna in what is otherwise vast and spartan sea scape. Passive continental margin cold seeps are typically attributed to the migration of hydrocarbons generated from deeply buried source rocks. Many of these seeps occur over salt tectonic provinces, where the movement of salt generates complex fault systems that can enable fluid migration or create seals and traps associated with reservoir formation. The elevated advective heat transport of the salt also produces a chimney effect directly over these structures. Here, we provide geophysical and geochemical evidence that the salt chimney effect in conjunction with diapiric faulting drives a subsurface groundwater circulation system that brings dissolved inorganic carbon, nutrient-rich deep basinal fluids, and potentially overlying seawater onto the crests of deeply buried salt diapirs. The mobilized fluids fuel methanogenic archaea locally enhancing the deep biosphere. The resulting elevated biogenic methane production, alongside the upward heat-driven fluid transport, represents a previously unrecognized mechanism of cold seep formation and regulation.

2.
Phys Rev Lett ; 132(12): 121902, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38579200

RESUMO

We report the measurement of the helicity asymmetry E for the pπ^{0} and nπ^{+} final states using, for the first time, an elliptically polarized photon beam in combination with a longitudinally polarized target at the Crystal Ball experiment at MAMI. The results agree very well with data that were taken with a circularly polarized photon beam, showing that it is possible to simultaneously measure polarization observables that require linearly (e.g., G) and circularly polarized photons (e.g., E) and a longitudinally polarized target. The new data cover a photon energy range 270-1400 MeV for the pπ^{0} final state (230-842 MeV for the nπ^{+} final state) and the full range of pion polar angles, θ, providing the most precise measurement of the observable E. A moment analysis gives a clear observation of the pη cusp in the pπ^{0} final state.

3.
Phys Rev Lett ; 118(21): 212001, 2017 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-28598665

RESUMO

The reactions γp→ηp and γp→η^{'}p are measured from their thresholds up to the center-of-mass energy W=1.96 GeV with the tagged-photon facilities at the Mainz Microtron, MAMI. Differential cross sections are obtained with unprecedented statistical accuracy, providing fine energy binning and full production-angle coverage. A strong cusp is observed in the total cross section for η photoproduction at the energies in the vicinity of the η^{'} threshold, W=1896 MeV (E_{γ}=1447 MeV). Within the framework of a revised ηMAID isobar model, the cusp, in connection with a steep rise of the η^{'} total cross section from its threshold, can only be explained by a strong coupling of the poorly known N(1895)1/2^{-} state to both ηp and η^{'}p. Including the new high-accuracy results in the ηMAID fit to available η and η^{'} photoproduction data allows the determination of the N(1895)1/2^{-} properties.

4.
Clin Oncol (R Coll Radiol) ; 34(1): e61-e68, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34728131

RESUMO

AIMS: Although health-related quality of life (HR-QoL) outcomes are pivotal in oncology, the prognostic significance of patient-reported HR-QoL metrics is largely undefined in localised prostate cancer. We report the association of baseline HR-QoL metrics with overall survival and toxicity in localised prostate cancer. MATERIALS AND METHODS: This was a secondary analysis of a phase III randomised controlled study conducted in a single-payer health system. Patients with Gleason score ≤7, clinical stage T1b-T3a and prostate-specific antigen <30 ng/ml were randomised to neoadjuvant and concurrent androgen deprivation therapy (ADT) for 6 months starting 4 months before prostate radiotherapy or concurrent and adjuvant ADT for 6 months starting simultaneously with prostate radiotherapy. HR-QoL scores were estimated using the European Organisation for Research and Treatment of Cancer QoL questionnaire. A multistate Markov model was used to determine the association of baseline HR-QoL metrics with overall survival and a multilevel multivariable Cox regression was used to determine the association with the incidence of delayed-onset grade ≥3 radiotherapy-related toxicities. To adjust for multiple analyses, P < 0.025 was considered as statistically significant. RESULTS: Overall, 393 patients with baseline HR-QoL data were included in this analysis: 194 in the neoadjuvant arm and 199 in the adjuvant arm. Baseline financial difficulty (hazard ratio 1.020, 95% confidence interval 1.010-1.030, P = 0.02) and dyspnoea (hazard ratio 1.020, 95% confidence interval 1.003-1.030, P = 0.01) were associated with inferior overall survival. Baseline dyspnoea was associated with a higher incidence of grade ≥3 toxicity (hazard ratio 1.020, 95% confidence interval 1.010-1.030, P = 0.023). CONCLUSION: In a cohort of localised prostate cancer patients treated with radiotherapy and short-term ADT, a 10-point higher baseline financial difficulty or dyspnoea was associated with a 20% increased risk of death. With each 10-point increase in baseline dyspnoea, we noted a 20% increase in the associated risk of grade ≥3 delayed-onset radiotherapy-related toxicity.


Assuntos
Neoplasias da Próstata , Qualidade de Vida , Antagonistas de Androgênios/efeitos adversos , Benchmarking , Humanos , Masculino , Medidas de Resultados Relatados pelo Paciente , Antígeno Prostático Específico , Neoplasias da Próstata/radioterapia
5.
Drug Dev Ind Pharm ; 36(2): 190-9, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19555247

RESUMO

PURPOSE: Purpose of this study was to develop storage stable pellets coated with the aqueous ethylcellulose dispersion Aquacoat ECD. METHODS: The influence of accelerated curing/storage conditions on the release behavior of Aquacoat/HPMC-coated drug pellets were investigated as a function of various formulations (sealing, plasticizer content, and pore-former type/amount) and process parameters (process humidity, thermal curing, and organic processing). RESULTS: Conventionally cured Aquacoat/hydroxypropyl methylcellulose- coated pellets were storage stable at ambient conditions and 25 degrees C/60% relative humidity (RH) but showed a decreasing drug release at 40 degrees C/75% RH, which is a required test condition according to ICH guidelines. CONCLUSION: Only organic processing of dried Aquacoat or unconventionally harsh curing conditions (60 degrees C/75% RH or 80 degrees C) improved the storage stability of Aquacoat-coated pellets at accelerated conditions.


Assuntos
Celulose/análogos & derivados , Excipientes/química , Celulose/química , Química Farmacêutica , Preparações de Ação Retardada/química , Composição de Medicamentos , Implantes de Medicamento/química , Estabilidade de Medicamentos , Armazenamento de Medicamentos/métodos , Umidade , Cinética , Plastificantes , Solubilidade , Temperatura
6.
Arch Gynecol Obstet ; 280(1): 59-64, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19084981

RESUMO

OBJECTIVE: To determine the pre-operative diagnosis by two dimensional ultrasound scan and the outcome of the laparoscopic management of cornual ectopic pregnancy. DESIGN: Prospective database cohort study. SETTING: Whipps Cross University Hospital, UK (District General Hospital). PATIENTS: Eleven patients with cornual ectopic pregnancy presenting in our hospital between January 2003 and December 2007. INTERVENTIONS: Laparoscopic cornuostomy or cornual resection. OUTCOME MEASURES: Pre-operative diagnosis by ultrasound scan, conversion rate to laparotomy, successful laparoscopy (not requiring further treatment), complication rate and duration of hospital stay. RESULTS: The mean gestational age was 8 +/- 2 weeks. All 11 patients presented with abdominal pain and vaginal bleeding and two (18%) patients became haemodynamically unstable before laparoscopy. There were five (45%) patients with risk factors for ectopic pregnancy. The mean serum beta-human chorionic gonadotropin (beta-hcg) was 15,263 +/- 12,045 microm/ml. One patient did not have a transvaginal scan as it was decided to proceed to surgery on clinical grounds. The diagnosis of ectopic pregnancy was correct at initial scan in nine (90%) of the ten patients who had transvaginal scans as one patient was misdiagnosed at the first scan. However, an ectopic pregnancy was diagnosed on a second ultrasound scan assessment. Initial laparoscopy was negative in one of the nine patients diagnosed as having an ectopic pregnancy. The diagnosis was later confirmed following serial serum beta-hcg monitoring, a repeat scan and a second laparoscopy. Ten (91%) of the 11 patients had successful operative laparoscopy as one (9%) patient had conversion to laparotomy. Among patients who had laparoscopic surgery, cornuostomy was performed in three (30%) patients while cornual resection was performed in the other seven (70%) patients. One (10%) of the patients who had laparoscopic surgery needed further treatment with systemic methotrexate. This patient had a cornual resection and was the only complication following laparoscopic surgery. The mean hospital stay was 2 days. CONCLUSION: This presentation of one of the larger series of patients with cornual ectopic pregnancy managed by laparoscopic surgery reveals that experience at ultrasonography and laparoscopic technique can lead to earlier diagnosis and few cases requiring laparotomy or further treatment. In addition laparoscopic surgery for cornual ectopic is safe and lends itself to conservative approach (cornuostomy) in selected cases.


Assuntos
Laparoscopia , Gravidez Ectópica/cirurgia , Adulto , Gonadotropina Coriônica Humana Subunidade beta/sangue , Diagnóstico Precoce , Feminino , Idade Gestacional , Humanos , Gravidez , Gravidez Ectópica/diagnóstico por imagem , Fatores de Risco , Ultrassonografia , Adulto Jovem
7.
Curr Oncol ; 16(3): 40-5, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19526084

RESUMO

Many modern radiotherapy centers now have image-guided intensity-modulated radiotherapy (IG-IMRT) tools available for clinical use, and the technique offers many options for patients requiring palliative radiotherapy. We describe a single-institution experience with IG-IMRT for short-course palliative radiotherapy, highlighting the unique situations in which the technique can be most effectively used.

8.
Curr Oncol ; 26(1): e81-e93, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30853813

RESUMO

Background: Little evidence has been generated for how best to manage patients with non-small-cell lung cancer (nsclc) presenting with rarer clinical scenarios, including oligometastases, oligoprogression, and pseudoprogression. In each of those scenarios, oncologists have to consider how best to balance efficacy with quality of life, while maximizing the duration of each line of therapy and ensuring that patients are still eligible for later options, including clinical trial enrolment. Methods: An expert panel was convened to define the clinical questions. Using case-based presentations, consensus practice recommendations for each clinical scenario were generated through focused, evidence-based discussions. Results: Treatment strategies and best-practice or consensus recommendations are presented, with areas of consensus and areas of uncertainty identified. Conclusions: In each situation, treatment has to be tailored to suit the individual patient, but with the intent of extending and maximizing the use of each line of treatment, while keeping treatment options in reserve for later lines of therapy. Patient participation in clinical trials examining these issues should be encouraged.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/epidemiologia , Neoplasias Pulmonares/epidemiologia , Qualidade de Vida/psicologia , Adulto , Canadá , Progressão da Doença , Guias como Assunto , Humanos , Masculino , Pessoa de Meia-Idade
9.
J Obstet Gynaecol ; 28(6): 614-7, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19003657

RESUMO

We set out to evaluate the effect of a programme introduced in January 2003 to make operative laparoscopy the standard surgical treatment for women requiring surgery for ectopic pregnancy. This was a retrospective and prospective clinical data analysis performed at The Whipps Cross University Hospital in London, with a comparison of data taken before and after the introduction of the programme. A total of 116 women who had surgical management for ectopic pregnancy from January 2000 to December 2002 and 313 women who had surgery for ectopic pregnancy between January 2003 and December 2006 took part in the study. A programme was started in January 2003 to make operative laparoscopy the surgical management of choice. The main outcome measure was the proportion of women requiring surgery who had operative laparoscopy in the two study periods. The chi(2)-test was used to determine if there was any statistically significant difference between proportions. A difference was deemed statistically significant if p < 0.05. The results showed that there was a progressive rise in the proportion of ectopic pregnancies managed by operative laparoscopy following the change in January 2003. A total of 34% of women were managed laparoscopically between 2000 and 2002, increasing to 90% between 2003 and 2006. This difference was statistically significant (p < 0.001). In 2006, some 96% of women requiring surgery were managed by laparoscopic surgery. The findings of this study indicate that it is possible to implement changes which increase and sustain a high rate of laparoscopic surgery for women with ectopic pregnancy requiring surgery in a district general hospital setting.


Assuntos
Hospitais Gerais , Laparoscopia/tendências , Gravidez Ectópica/cirurgia , Adulto , Feminino , Hospitais de Distrito , Humanos , Londres , Gravidez , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento , População Urbana/estatística & dados numéricos
10.
J Obstet Gynaecol ; 28(7): 683-7, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19065360

RESUMO

In October 2003, The National Institute for Clinical Excellence recommended screening tests for Down's syndrome (DS) to come into effect from April 2007. These tests were recommended based on studies performed in research centres. Some of the recommended tests have a fetal nuchal translucency scan component. In this retrospective study at the Basildon and Thurrock University Hospital we have evaluated nuchal translucency (NT) scans performed between July 1998 and January 2004 on 18,965 fetuses with a view to comparing our findings with research centres. In spite of our high standards, our detection rate for DS was 72.0% (95% CI 56.0-83.8%) for a 5% false positive rate. This was much lower than the 85% reported from the seminal paper in 1994. We believe that the advice given to women should be based on data from working programmes and not research units.


Assuntos
Síndrome de Down/diagnóstico , Medição da Translucência Nucal/estatística & dados numéricos , Reações Falso-Positivas , Feminino , Hospitais Gerais , Humanos , Gravidez , Estudos Retrospectivos , Sensibilidade e Especificidade
11.
Nurse Educ Today ; 71: 205-210, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30296731

RESUMO

Increasing numbers of people with dementia are living longer with a higher likelihood of requiring hospital care for physical conditions including falls, infections and stroke (Boaden, 2016). However, the literature is replete with descriptions of poor care and hospital care experiences that have fallen well below the expectations of people with dementia, their families and friends. Although poor care is unacceptable, it is unsurprising given that dementia education for health and social care professionals is often inadequate and inconsistent. This results in most healthcare staff being ill-equipped and lacking the confidence to work with people living with dementia. The first of Scotland's National Dementia Strategies committed to "improve the response to dementia in general hospital settings including alternatives to admission and better planning for discharge" (Scottish Government, 2010). The educational response was the commissioning of the Dementia Champions programme. Since 2011, the programme has developed over 800 health and social care professionals working in general hospital and related settings to be change agents in dementia care. This article will outline the theoretical underpinning of the programme and present pooled results from four cohorts (2014-2017) (n = 524). A repeated measure design (pre and post programme) was used to measure attitudes towards people with dementia; self-efficacy and knowledge of dementia. The findings suggest that the education had a statistically significant positive effect on all intended outcomes, indicating the potential for practice change. We discuss these findings in relation to the literature, and respond to the calls for high quality evaluation to measure the effectiveness of dementia education, the challenges and potential directions for measuring educational effectiveness and capturing transfer of learning.


Assuntos
Competência Clínica/normas , Demência/terapia , Educação Continuada em Enfermagem/normas , Enfermeiras e Enfermeiros/psicologia , Atitude do Pessoal de Saúde , Demência/psicologia , Educação Continuada em Enfermagem/métodos , Humanos , Enfermeiras e Enfermeiros/estatística & dados numéricos , Avaliação de Programas e Projetos de Saúde/métodos , Escócia , Inquéritos e Questionários
12.
J Control Release ; 105(3): 226-39, 2005 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-15946758

RESUMO

Blends of aqueous dispersions of a water-insoluble and an enteric polymer, namely ethyl cellulose:hydroxypropyl methylcellulose acetate succinate (EC:HPMCAS) and ethyl cellulose:methacrylic acid ethyl acrylate copolymer (EC:Eudragit L), were used as coating materials to control theophylline release from matrix pellets. Varying the polymer blend ratio, broad ranges of drug release patterns were obtained at low as well as at high pH. Interestingly, the resulting release profiles were rather similar for both types of blends in 0.1 M HCl, whereas significant differences were observed in phosphate buffer pH 7.4. Surprisingly, drug release at high pH was much slower for EC:HPMCAS blends compared to EC:Eudragit L blends, although HPMCAS leached out more rapidly (and to a higher extent) from the film coatings than Eudragit L. To explain these phenomena and to better understand the underlying drug release mechanisms, thin polymeric films of identical composition as the pellet coatings were prepared and physicochemically characterized before and upon exposure to the release media. Importantly, the polymer particle size was identified to be a very crucial formulation parameter, determining the resulting film coating structure and properties. The Eudragit L particles are much smaller than the HPMCAS particles (nano- vs. micrometer size range) and, thus, more effectively hinder the formation of a continuous and mechanically stable EC network. Consequently, the EC structures remaining after enteric polymer leaching at high pH are mechanically much weaker in the case of Eudragit L. Upon exposure to phosphate buffer, water-filled cracks are formed, through which the drug rapidly diffuses out. In contrast, the EC structures remaining upon HPMCAS leaching are mechanically stronger and drug release is controlled by diffusion through the polymeric remnants.


Assuntos
Portadores de Fármacos/química , Polímeros/química , Celulose/análogos & derivados , Fenômenos Químicos , Físico-Química , Cromatografia Líquida de Alta Pressão , Formas de Dosagem , Estabilidade de Medicamentos , Emulsões , Testes de Dureza , Cinética , Metilcelulose/análogos & derivados , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Plastificantes , Ácidos Polimetacrílicos , Propriedades de Superfície , Teofilina/administração & dosagem , Teofilina/química
13.
Eur J Pharm Biopharm ; 60(1): 73-80, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15848059

RESUMO

The effect of SBE7-beta-cyclodextrin together with hydroxypropylmethyl cellulose (HPMC) or polyvinylpyrrolidone (PVP) on the saturated solubility and delivery of carbamazepine (a poorly soluble drug) from sustained release (SR) beads was investigated. Carbamazepine solubility at room temperature increased from 0.1 to 5.4mg/ml by forming an inclusion complex with SBE7-beta-cyclodextrin (15%w/v). HPMC (0.1%w/v) also increased the aqueous solubility of carbamazepine, acting both alone and synergistically with SBE7-beta-cyclodextrin, to produce solubility values of 0.26 and 8.1mg/ml respectively. PVP (0.1-0.5%w/v) had no effect on carbamazepine solubility, either alone or in combination with SBE7-beta-cyclodextrin. The addition of SBE7-beta-cyclodextrin to SR beads increased the rate of carbamazepine release. In addition, comparable release rates where obtained when lower ratios of SBE7-beta-cyclodextrin together HPMC were incorporated in the SR bead. Therefore this ternary drug cyclodextrin polymer system was considered preferable over the binary drug cyclodextrin system for SR beads, as less cyclodextrin was required. However, both binary and ternary approaches were considered suitable techniques to improve the release rate and potentially the in vivo bioavailability of poorly soluble drugs that had previously exhibited slow or incomplete release from SR beads.


Assuntos
Carbamazepina/administração & dosagem , Excipientes/química , beta-Ciclodextrinas/química , Algoritmos , Carbamazepina/química , Química Farmacêutica , Preparações de Ação Retardada , Concentração de Íons de Hidrogênio , Derivados da Hipromelose , Metilcelulose/análogos & derivados , Povidona , Solubilidade , Espectrofotometria Ultravioleta
14.
Semin Oncol ; 28(4 Suppl 14): 17-22, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11605179

RESUMO

The results of randomized trials have prompted an evolution in the treatment approach to inoperable locally advanced non-small cell lung cancer, from radiotherapy alone to sequential chemoradiotherapy and now to concurrent chemoradiotherapy. The improvement in outcome seen with a concurrent chemoradiotherapy approach may be because of spatial cooperation, enhanced radiosensitization, and/or enhanced cytotoxicity. The taxanes, specifically paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ), delivered in combination with radiation have been extensively examined in both preclinical and clinical studies. Several mechanisms have been suggested to explain the enhanced tumor cell kill seen with paclitaxel and radiation, and phase II studies have examined this combination in the setting of inoperable stage III non-small cell lung cancer. This review will explore some of the studies with this treatment approach in locally advanced disease. We also will briefly discuss some of the ongoing trials that are attempting to refine the delivery of concurrent thoracic radiation and paclitaxel-based chemotherapy.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Paclitaxel/uso terapêutico , Radiossensibilizantes/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Ensaios Clínicos como Assunto , Terapia Combinada , Avaliação Pré-Clínica de Medicamentos , Humanos , Neoplasias Pulmonares/radioterapia
15.
J Control Release ; 89(3): 457-71, 2003 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-12737848

RESUMO

THE OBJECTIVES OF THIS STUDY WERE: (i). to use blends of gastrointestinal tract (GIT)-insoluble and enteric polymers (ethyl cellulose and Eudragit L) as coating materials for multiparticulate controlled release dosage forms; (ii). to investigate the effects of the polymer blend ratio and coating level on the resulting drug release patterns; and (iii). to explain the observed phenomena based on the physicochemical properties of the systems. Propranolol HCl-loaded pellets were coated in a fluidized bed coater with organic polymer solutions; thin, drug-containing and drug-free, polymeric films were prepared using a casting knife. In vitro drug release, water uptake and dry weight loss studies were performed in 0.1 M HCl and phosphate buffer pH 7.4, respectively. The apparent drug diffusion coefficients within the polymeric systems were determined using different experimental and theoretical techniques (side-by-side diffusion cells, in vitro drug release from thin films; exact and approximate solutions of Fick's second law of diffusion). A broad range of drug release patterns from coated pellets could be achieved by varying the GIT-insoluble:enteric polymer blend ratio. With increasing relative amounts of Eudragit L, the release rates in both media significantly increased. The increase at low pH could be attributed to an increase in water uptake, as observed with thin films. Interestingly, only partial Eudragit L leaching occurred in phosphate buffer pH 7.4 even at high enteric polymer contents, indicating that the GIT-insoluble polymer effectively hindered the dissolution of the entrapped Eudragit L. At high pH, both polymer leaching and polymer swelling contributed to the control of drug release. The determined apparent drug diffusion coefficients take the two effects adequately into account.


Assuntos
Celulose/análogos & derivados , Polímeros/química , Polímeros/farmacocinética , Comprimidos com Revestimento Entérico/química , Comprimidos com Revestimento Entérico/farmacocinética , Celulose/química , Celulose/farmacocinética , Fenômenos Químicos , Físico-Química , Preparações de Ação Retardada , Sistema Digestório/metabolismo , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/farmacocinética , Solubilidade
16.
J Control Release ; 99(1): 1-13, 2004 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-15342176

RESUMO

The aim of this study was to investigate the importance of the type of plasticizer in polymer blends used for the coating of solid dosage forms, comparing a lipophilic and a hydrophilic plasticizer (dibutyl sebacate (DBS) and triethyl citrate (TEC)). In vitro drug release from propranolol hydrochloride (propranolol HCl)-loaded pellets coated with blends of ethyl cellulose (EC) and Eudragit L (100:0, 75:25, 50:50, 25:75 and 0:100 w/w) was investigated at low as well as at high pH. To better understand the underlying mass transport mechanisms, the physicochemical properties of the film coatings (e.g. mechanical resistance, water uptake and dry weight loss behavior) were determined. Interestingly, drug release strongly depended on the type of plasticizer. Importantly, not only the slope but also the shape of the release curves was affected, indicating that the chemical nature of the plasticizer plays a major role for the underlying drug release mechanisms. Diffusion through the intact polymer coatings and/or through water-filled cracks was found to be dominating for the control of drug release. The relative importance of these pathways strongly depended on the polymer blend ratio and type of plasticizer. In contrast to DBS, TEC rapidly leached out of the coatings, resulting in decreasing mechanical resistances of the films and, thus, facilitated crack formation. In addition, the hydrophilicity of the plasticizer significantly affected the water uptake behavior of the film coatings and, hence, changes in the coatings' toughness and drug permeability. Also the relative affinity of the plasticizer to the different polymers was found to be of significance. In contrast to TEC, DBS has a higher affinity to EC than to Eudragit L, resulting in potential redistributions of this plasticizer within the polymeric systems and changes in the release profiles during storage. Importantly, these effects could be avoided with appropriate curing conditions and preparation techniques for the coating dispersions.


Assuntos
Preparações de Ação Retardada/química , Plastificantes/química , Polímeros/química , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Propranolol/química , Fatores de Tempo , Água/química
17.
Clin Lung Cancer ; 2 Suppl 2: S34-40, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-14725728

RESUMO

Locally advanced non small-cell lung cancer (NSCLC) represents 30%-40% of all pulmonary malignancies. Despite the fact that the disease is confined to the chest, most patients will eventually succumb to their dis-ease. Therefore, the management of NSCLC is undergoing rapid evolution with hope of improving overall survival. The arrival of a new generation of chemotherapeutic agents, including the taxanes, gemcitabine, and topoisomerase inhibitors such as irinotecan and topotecan, offers the hope of real advances against this malignancy. Irinotecan and topotecan are camptothecin derivatives that are felt to exert their cytotoxic effects by targeting topoisomerase I. It is believed that topoisomerase I inhibitors stabilize a DNA-topoisomerase I cleavable complex, and interactions between this complex and the replication machinery may lead to cell death. There is a significant volume of in vitro and in vivo data demonstrating that these topoisomerase I inhibitors also act as radiosensitizers. Early clinical data with topotecan suggests that it is a more active agent in small-cell lung cancer than it is in NSCLC despite a common mechanism of action with irinotecan. With the increasing data that exist on the improved outcome with concurrent chemoradiation treatment for malignancies including lung cancer and head and neck cancers, there is an impetus to pursue the addition of other drugs that can radiosensitize tumors and further improve local control. Irinotecan is undergoing early clinical trials in the combined modality setting in several different disease sites. This paper will review the in vitro and in vivo data on the ability of irinotecan and topotecan to render tumors more susceptible to ionizing radiation. It will then focus on the experience with both drugs and thoracic radiation in the treatment of NSCLC, in which irinotecan has yielded acceptable toxicity results and response rates in excess of 60% in early trials. It is hoped that newer treatment strategies, such as the combination of radiation and topoisomerase I inhibitors in lung cancer, will have a significant impact on cure rates in the future.

18.
Oncology (Williston Park) ; 15(1 Suppl 1): 31-6, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11221019

RESUMO

The management of non-small-cell lung cancer is undergoing rapid evolution. Although the advent of combined-modality therapy has led to improved survival, most patients eventually succumb to the disease. The arrival of a new generation of chemotherapeutic agents--including the taxanes, gemcitabine (Gemzar), and topoisomerase inhibitors such as irinotecan (Camptosar, CPT-11)--offers the hope of advances against this malignancy. Irinotecan, a camptothecin derivative, has shown impressive activity in a variety of solid tumors, including non-small-cell lung cancer. It is believed to act by stabilizing the topoisomerase-DNA complex formed during diverse cellular processes, including replication and transcription. A considerable body of evidence also demonstrates that camptothecin and its derivatives possess substantial radiosensitization properties. This article will review the in vitro and in vivo data on irinotecan's ability to render tumors more susceptible to ionizing radiation. It will then focus on experience with irinotecan and thoracic radiation in the treatment of non-small-cell lung cancer, which has yielded acceptable toxicity results and response rates in excess of 60% in early trials. It is hoped that newer treatment strategies--such as the combination of radiation and irinotecan in lung cancer--will significantly impact cure rates in the future.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Camptotecina/análogos & derivados , Camptotecina/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Terapia Combinada , Humanos , Irinotecano , Neoplasias Pulmonares/radioterapia , Taxa de Sobrevida
19.
Oncology (Williston Park) ; 15(7 Suppl 8): 22-8, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11497228

RESUMO

Irinotecan (CPT-11, Camptosar) is a camptothecin derivative that is thought to exert its cytotoxic effects by targeting topoisomerase I. It is believed that irinotecan stabilizes a DNA-topoisomerase I cleavable complex, and that interactions between this complex and the replication machinery may lead to cell death. There is a significant volume of in vitro and in vivo data demonstrating that irinotecan acts as a radiosensitizer. The exact mechanism of this radiosensitization is currently unknown. The increasing amount of data demonstrating improved outcomes with concurrent chemoradiation treatment of malignancies like lung cancer and head and neck cancer provide impetus for pursuing the addition of other drugs as radiosensitizers to improve local control further. Irinotecan is undergoing early clinical trials in the combined-modality setting in several disease sites. This article will provide an overview of the current status of irinotecan used concurrently with radiotherapy in the treatment of a variety of solid tumors.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Camptotecina/análogos & derivados , Camptotecina/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Inibidores da Topoisomerase I , Antineoplásicos Fitogênicos/administração & dosagem , Camptotecina/administração & dosagem , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Esquema de Medicação , Inibidores Enzimáticos/uso terapêutico , Feminino , Neoplasias Gastrointestinais/tratamento farmacológico , Neoplasias Gastrointestinais/radioterapia , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Irinotecano , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Masculino , Radioterapia Adjuvante , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/radioterapia
20.
Expert Opin Pharmacother ; 2(6): 963-74, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11585012

RESUMO

The plant-derived taxanes have a unique mechanism of cytotoxic action and have shown interesting response and survival data in metastatic non-small cell lung cancer (NSCLC). Based on these results, taxane-based regimens have been investigated in combination with radiotherapy in unresectable NSCLC. Trials with paclitaxel-based concurrent chemoradiotherapy have shown 50-100% tumour response rates, 12-26 month median survivals and 32-52% 2-year survival rates. Trials with concurrent chemoradiotherapy with docetaxel have shown 35-92% tumour response rates, 12-23 month median survivals, and 41-43% 2 year survival rates. Taxane-based concurrent chemoradiotherapy for stage III NSCLC appears promising. Large ongoing randomised trials will define the role of these agents in the treatment of locally advanced NSCLC.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Hidrocarbonetos Aromáticos com Pontes/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Taxoides , Carcinoma Pulmonar de Células não Pequenas/patologia , Ensaios Clínicos como Assunto , Terapia Combinada , Docetaxel , Guias como Assunto , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/radioterapia , Estudos Multicêntricos como Assunto , Estadiamento de Neoplasias , Paclitaxel/análogos & derivados , Paclitaxel/uso terapêutico , Resultado do Tratamento
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