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1.
Sci Rep ; 14(1): 2878, 2024 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-38311635

RESUMO

Although the risk of cancer progression in a Barrett's esophagus (BE) is very low, worrying about cancer is known as an important factor affecting HRQoL. The aim of this study was to determine the proportion of BE patients with high levels of worry for cancer, to compare outcomes of patients endoscopically treated for BE neoplasia (DBE), non-dysplastic BE patients (NDBE) and patients with reflux symptoms, and to examine associated factors. We performed a cross sectional, exploratory, self-administered questionnaire study using the cancer worry scale, and the reflux disease questionnaire. A total of 192 DBE patients, 213 NDBE patients and 111 refractory reflux symptom patients were included from October 2019 until July 2021, 76.8% of BE participants were male and aged 66.9 years. High cancer worry was reported in 40.6% of the DBE patients and 36.2% of NDBE patient. Reflux patients scored statistically significant worse with 56.6% stated high cancer worry. Positive correlations were found between reflux symptoms and cancer worry in NDBE patients and reflux patients. In DBE patients' negative correlations were found between higher cancer worry and younger age as well as a family history of esophageal carcinoma. A clinically significant group of BE patients reported high cancer worry, which was associated with reflux symptoms in NDBE patients and a younger age and a (family) history of esophageal carcinoma diagnosis in BE patients treated for (early) neoplasia. Physicians should communicate about the actual cancer risk, which leads to greater patient understanding and therefore may have a positive impact on health outcomes.


Assuntos
Adenocarcinoma , Esôfago de Barrett , Neoplasias Esofágicas , Refluxo Gastroesofágico , Humanos , Masculino , Feminino , Esôfago de Barrett/epidemiologia , Esôfago de Barrett/complicações , Prevalência , Estudos Transversais , Adenocarcinoma/patologia , Neoplasias Esofágicas/patologia , Refluxo Gastroesofágico/complicações , Refluxo Gastroesofágico/epidemiologia
2.
Int Urol Nephrol ; 54(6): 1391-1398, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34661825

RESUMO

BACKGROUND: Peritoneal dialysis (PD) catheters can be obstructed by omental wrapping or migration, leading to catheter malfunction. Multiple catheter placement techniques have been described. Advanced laparoscopy with fixation of the catheter and omentum has been reported to improve functional outcome compared to basic laparoscopy without fixation. This feasibility study describes surgical technique, complications, and comparison of the functional outcome of advanced versus basic laparoscopic catheter placement. METHODS: Between July 2016 and April 2019, the advanced laparoscopy technique was applied in all eligible patients. Two experienced surgeons placed the catheters in a standardized procedure. Peri-operative complications and functional outcome of the catheter were scored. Results were compared to a historical cohort retrieved from our RCT performed earlier using basic laparoscopy. FINDINGS: The basic laparoscopic group (BLG) consisted of 46 patients and the advanced laparoscopic group (ALG) of 32. Complication rate in both groups was similar and low with 7% in the BLG and 6% in the ALG (p = 1.0). There was a trend toward better functional catheter outcome in the ALG (88%) compared to the BLG (70%) (p = 0.1). Part of the catheter failures in the ALG could be related to the learning curve. After revision surgery, 94% of patients in the ALG had a functional catheter. These findings lead to the set-up of a multi-center randomized-controlled trial, currently running, comparing basic to advanced laparoscopic techniques.


Assuntos
Falência Renal Crônica , Laparoscopia , Diálise Peritoneal , Cateterismo/métodos , Catéteres , Cateteres de Demora , Feminino , Hospitais Universitários , Humanos , Laparoscopia/métodos , Masculino
3.
Home Health Care Serv Q ; 40(4): 262-275, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34467831

RESUMO

The aim was to investigate the views of stakeholders on the practical relevance of a broad quality of life (QoL) outcome tool for care in older adults: the Extended Quality of Life Tool (EQLT). We conducted individual interviews and focus groups with a variety of stakeholders involved in the care for older adults which were analyzed using a framework analysis. Stakeholders considered relevant: focus on the client perspective; perspective on QoL broader than health; the possibility to take diversity into account; and the possibility to determine a minimum level of QoL. Three facilitators for implementation of the tool were mentioned as well as four barriers. The EQLT can support conversations with clients about their needs and wishes, thus enabling decisions about care services based on a broad set of domains of QoL. Implementation of the tool should take into account the facilitators and barriers identified in the current study.


Assuntos
Qualidade de Vida , Idoso , Grupos Focais , Humanos
4.
J Radiol Prot ; 41(3)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-33975282

RESUMO

The aim of this work was to investigate the effect of patient and cohort size on the overall uncertainty associated with dose audit using radiography of the abdomen as the exemplar. Water equivalent diameterDwwas used as the surrogate for patient size and its distribution (σ(Dw)) was used to quantify the effect of sample size. The more precise the kerma area product calibration, the more patients are required in the cohort to have the same impact on the overall uncertainty. Patient sample sizes of 300-400 will result in expanded uncertainties approaching the theoretical limit of double the measurement uncertainty when audits are performed with instruments having measurement uncertainties equal to ±7%, ±10% or ±12.5%. By way of example, for a field instrument with a measurement uncertainty of ±10%, a minimum sample size of 350 is required to achieve a total expanded uncertainty of ±21%. In the case of instruments with associated measurement uncertainty of ±3.5%, patient sample sizes of 300-400 will result in expanded uncertainties of approximately ±10%. From review of the literature and comparison with the results obtained here, it is conjectured that for radiographic dose audits of all parts of the trunk the contribution to overall uncertainty due to patient and sample size could be predicted using an indicative value forσ(Dw) of 3.4 where local data is not available.


Assuntos
Incerteza , Calibragem , Estudos de Coortes , Humanos , Radiografia
5.
BMC Med Educ ; 20(1): 250, 2020 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-32758215

RESUMO

BACKGROUND: In medical physiology, educators and students face a serious challenge termed misconceptions. Misconceptions are incorrect ideas that do not match current scientific views. Accordingly, they have shown to hamper teaching and learning of physiological concepts. Conceptual Change Theory forms the basis of new teaching and learning practices that may alleviate misconceptions and facilitate critical thinking skills that are essential in becoming knowledgeable, self-regulated health professionals. In this study, we examined if such an intervention named refutation texts, could enhance medical students' cognition and metacognition. METHODS: First-year medical students (N = 161) performed a pre-test and post-test on cardiovascular physiology concepts, including a self-perceived confidence rating. In between, students read either a standard text with an explanation of the correct answer, or a refutation text which additionally refuted related misconceptions. RESULTS: In both groups, average performance scores (refutation: + 22.5%, standard: + 22.8%) and overall confidence ratings (refutation: Δ0.42 out of 5, standard: Δ0.35 out of 5) increased significantly (all p < .001), but a significant effect of the specific refutation element was not found. Initially incorrect answers were corrected less frequently in cases of high confidence (35.8%) than low confidence (61.4%). CONCLUSIONS: Our results showed that refutation texts significantly increased students' knowledge, however, the refutation element did not have a significant additional effect. Furthermore, high confidence in incorrect answers negatively affected the likelihood of correction. These findings provide implications for teaching practices on concept learning, by showing that educators should take into account the key role of metacognition, and the nature of misconceptions.


Assuntos
Fisiologia , Estudantes de Medicina , Formação de Conceito , Humanos , Conhecimento , Aprendizagem , Leitura
6.
Qual Life Res ; 27(5): 1181-1189, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29243043

RESUMO

PURPOSE: Economic evaluation of services and interventions in care services tends to focus on quality of life(QoL) based on health-related measures such as EQ5D, with a major focus on health and functioning. The Capability Approach (CA) provides an alternative framework for measuring QoL and challenges some of the conventional issues in the current practice of measurement of QoL. The Adult Social Care Outcomes Toolkit (ASCOT) aims to measure social care-related QoL in a broad sense. This article investigates whether and, if so, how the ASCOT addresses issues put on the agenda by the CA. METHODS: Literature analysis concerning theoretical assumptions and arguments of CA and ASCOT. RESULTS: The Capability Approach (CA) puts three issues on the agenda regarding QoL. First, the focus of evaluation should not be on functioning, but on freedom of choice. Second, evaluation should be critical about adaptive preferences, which entail that people lower expectations in situations of limited possibilities. Third, evaluation should not only address health, but also other domains of life. Our analysis shows that freedom of choice is reflected in the response option 'as I want' in the ASCOT questionnaire. The problem of adaptive preferences is countered in the ASCOT by developing a standard based on preferences of the general population. Third, the ASCOT contains several domains of life. CONCLUSIONS: We conclude that the CA and the ASCOT contribute to the discussion on QoL, and that the ASCOT operationalizes core assumptions of the CA, translating the issues raised by the CA in a practical way.


Assuntos
Comportamento de Escolha , Análise Custo-Benefício/métodos , Nível de Saúde , Qualidade de Vida/psicologia , Inquéritos e Questionários , Idoso , Feminino , Humanos , Masculino
8.
Eur J Vasc Endovasc Surg ; 49(6): 738-743, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25888467

RESUMO

BACKGROUND: Adequate functioning vascular access is the key to successful hemodialysis. The use of an autologous arteriovenous fistula (AVF) is advised because of good long-term patency and a low incidence of complications. However, the number of patients with AVFs is declining because of the change in the demography of the dialysis population, with increasing numbers of very old patients with multiple comorbidities. METHODS: In this vignette an elderly patient is described with calcified distal arteries and a small cephalic vein who is referred at a late stage for access creation. The results and performance of different types of vascular access (AVF; arteriovenous graft; central vein catheter), in relation to late referral and patient demographics, are described. In addition, patient morbidity and mortality versus the type of access are discussed. CONCLUSIONS: The patient described in this vignette appears to be unsuitable for the creation of a forearm AVF because of calcified distal arteries and a small cephalic vein. The risk of non-maturing autologous AVFs is high in elderly patients and this observation might justify the use of early stick grafts. High risk patients may benefit from permanent central vein catheters.


Assuntos
Derivação Arteriovenosa Cirúrgica , Implante de Prótese Vascular , Cateterismo Venoso Central , Falência Renal Crônica/terapia , Diálise Renal , Extremidade Superior/irrigação sanguínea , Calcificação Vascular/complicações , Fatores Etários , Idoso , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Derivação Arteriovenosa Cirúrgica/mortalidade , Implante de Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/mortalidade , Cateterismo Venoso Central/efeitos adversos , Cateterismo Venoso Central/mortalidade , Comorbidade , Humanos , Falência Renal Crônica/complicações , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/mortalidade , Masculino , Seleção de Pacientes , Diálise Renal/efeitos adversos , Diálise Renal/mortalidade , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Calcificação Vascular/diagnóstico
9.
Int J Otolaryngol ; 2011: 845879, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22229033

RESUMO

Objective. To describe the audiological, anesthesiological, and surgical key points of cochlear implantation after bacterial meningitis in very young infants. Material and Methods. Between 2005 and 2010, 4 patients received 7 cochlear implants before the age of 9 months (range 4-8 months) because of profound hearing loss after pneumococcal meningitis. Results. Full electrode insertions were achieved in all operated ears. The audiological and linguistic outcome varied considerably, with categories of auditory performance (CAP) scores between 3 and 6, and speech intelligibility rating (SIR) scores between 0 and 5. The audiological, anesthesiological, and surgical issues that apply in this patient group are discussed. Conclusion. Cochlear implantation in very young postmeningitic infants is challenging due to their young age, sequelae of meningitis, and the risk of cochlear obliteration. A swift diagnostic workup is essential, specific audiological, anesthesiological, and surgical considerations apply, and the outcome is variable even in successful implantations.

10.
Eur J Vasc Endovasc Surg ; 39(3): 333-9, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20060754

RESUMO

OBJECTIVE: Successful access cannulation is of utmost importance for adequate hemodialysis treatment. Upper arm fistulae, obesity and deep or tortuous veins may impair needling and can cause significant complications and inconvenience for the patient. In the ultimate case, cannulation problems lead to temporary central vein catheter use for dialysis or even to irreversible access loss. Surgical access revision may enhance successful cannulation. METHODS: A systematic literature review of all publications related to hemodialysis vascular access, cannulation complications and treatment was performed. RESULTS: A total of 384 publications were identified, of which only 17 were related to treatment of cannulation complications in large patient populations. The clinical success rate of surgical intervention with vein elevation or transposition ranges from 85% to 91%. The 1-year primary and secondary patencies are 60% and 71%, respectively. Lipectomy results in an initial success rate of 100% with a primary and secondary patency of 71% and 98%, respectively, after 1 year of follow-up. CONCLUSION: Surgical revision to improve hemodialysis vascular access cannulation has a high clinical success rate with good long-term patency.


Assuntos
Derivação Arteriovenosa Cirúrgica , Implante de Prótese Vascular , Cateterismo , Diálise Renal , Extremidade Superior/irrigação sanguínea , Procedimentos Cirúrgicos Vasculares , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Implante de Prótese Vascular/efeitos adversos , Cateterismo/efeitos adversos , Humanos , Ligadura , Lipectomia , Obesidade/complicações , Reoperação , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Grau de Desobstrução Vascular , Veias/patologia , Veias/cirurgia
11.
Ann Trop Paediatr ; 29(3): 231-4, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19689867

RESUMO

An 8-year-old girl presented with severe muscular weakness, peripheral neuropathy, ataxia, fever and macrocytic anaemia. Clinically, vitamin B(12) (cobalamin) deficiency was considered. Despite the lack of pre-treatment laboratory confirmation of the diagnosis, a therapeutic trial of hydroxocobalamin injections was begun. After several days, a partial clinical response was seen. Within 5 months all symptoms had resolved. After treatment was initiated, laboratory analysis of pre-treatment blood samples confirmed the presence of vitamin B(12) deficiency. Auto-antibodies to intrinsic factor and parietal cells, pathognomonic for pernicious anaemia, were confirmed. Vitamin B(12) deficiency owing to dietary deficiency is not uncommon in children in developing countries. Although nutritional deficiency might have played a role in our patient, this case illustrates that the neurological manifestations of pernicious anaemia can present at a young age in African populations.


Assuntos
Anemia Perniciosa/diagnóstico , Hematínicos/uso terapêutico , Hidroxocobalamina/uso terapêutico , Anemia Perniciosa/complicações , Anemia Perniciosa/tratamento farmacológico , Ataxia/etiologia , Criança , Diagnóstico Precoce , Feminino , Humanos , Debilidade Muscular/etiologia , Doenças do Sistema Nervoso Periférico/etiologia , Deficiência de Vitamina B 12/diagnóstico
12.
Zoo Biol ; 28(2): 98-106, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19367623

RESUMO

A feeding trial was performed on adult rainbow lorikeets of two subspecies: six green-naped lorikeets (Trichoglossus haematodus haematodus) and six red-breasted lorikeets (T. haematodus mitchellii). Throughout the entire trial, half of the birds from each subspecies had ad libitum access to water-diluted commercial nectar powder and drinking water only, whereas the other half also received ad libitum apple pieces. During three consecutive 14-d periods, the nectar powder was diluted to a different degree: 1:3 (low), 1:5 (high) and 1:4 (medium) (v:v). Diluting nectar to a higher degree resulted in both subspecies in a decrease in voluntary energy intake. Next, nectar intake significantly decreased when apple was available and apple intake significantly increased when fed higher-diluted nectar. In green-naped lorikeets fed nectar and apple, energy intake was similar between dilution degrees of nectar but was lower compared with feeding only low- or medium-diluted nectar. Whereas, in red-breasted lorikeets, provision of apple next to medium- or high-diluted nectar resulted in higher voluntary energy intake compared with feeding solely nectar of any degree. Overall, protein and thiamine intake as well as Ca:P ratio of the ingested ration were lowest when fed highly diluted nectar and apple. Yet, minimal requirements were still covered. Because energy content of fruit can be higher than liquid diets, in this case medium- or high-diluted nectar, ad libitum provision of fruit as a means to lower voluntary energy intake in lorikeets, for instance in case of obesity, needs to be considered with care.


Assuntos
Dieta/veterinária , Comportamento Alimentar/fisiologia , Frutas , Psittaciformes/classificação , Psittaciformes/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Animais de Zoológico , Ingestão de Alimentos , Especificidade da Espécie
13.
Nephrol Dial Transplant ; 22(6): 1628-32, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17400567

RESUMO

INTRODUCTION: In the Netherlands an access quality improvement plan (QIP) was introduced by vascular access coordinators (VAC) with the aim to decrease vascular access-related complications by preemptive intervention of malfunctioning accesses. A vascular access QIP was established in 24 centres (46% of all Dutch facilities) and a structural multidisciplinary vascular access meeting was instituted. In these centres, including 2300 patients, a protocol for enhancement of fistula creation and access surveillance programme was implemented, with instruction of physicians and nurses, and rounds to discuss complications and evaluate vascular access interventions. The number and type of vascular access, permanent catheters, thrombosis rates and number of interventions were evaluated at the start and end of the study period. RESULTS: After the surveillance programme, the number of autogenous arterio-venous fistulas (AVFs) had increased significantly from 69 to 77% (P < 0.01), while the use of temporary subclavian vein catheters declined (34% vs 11%) (P < 0.01), with a substantially higher percentage of jugular vein catheters (from 23 to 35%). Interventional treatment of malfunctioning accesses by percutaneous transluminal angioplasty (PTA) (from 0.39 to 0.50 patient/year; P < 0.001)) and surgical revisions (from 0.06 to 0.12 per patient/year; P < 0.001) also increased. CONCLUSION: These data demonstrate that a vascular access QIP resulted in placement of more autogenous AVFs, increased number of PTAs and surgical interventions. These findings suggest that a vascular access care QIP is worthwhile to improve dialysis patients' care and access morbidity.


Assuntos
Cateteres de Demora/normas , Garantia da Qualidade dos Cuidados de Saúde/normas , Diálise Renal/normas , Cateteres de Demora/efeitos adversos , Humanos , Nefropatias/terapia , Distribuição Aleatória , Resultado do Tratamento
14.
Ann Rheum Dis ; 63(9): 1056-61, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15115713

RESUMO

BACKGROUND: T cells have a pivotal role in RA. Leflunomide inhibits pyrimidine biosynthesis, to which T cells are especially susceptible, and therefore may have a different cytokine profile than methotrexate. MATERIALS AND METHODS: Serum samples of 100 patients with RA, treated with leflunomide (n = 50) or methotrexate (n = 50), were collected at baseline, after 16 weeks and after 1 year's treatment. Serum levels of interleukin 6 (IL6), and interferon (IFN) gamma were determined by ELISA. Additionally, peripheral blood mononuclear cells (PBMC) of five healthy volunteers and three patients with RA were isolated and the effects of the active metabolite of leflunomide (A77-1726, 0-200 mmol/l) on cell proliferation and on IL6 and IFNgamma production were determined by ELISA. In peripheral blood lymphocytes (PBL) and monocytes (PBM) from two healthy volunteers the effects of A77-1726 on IL6 production were measured by ELISA and PCR. RESULTS: Mean (SEM) serum levels of IFNgamma were significantly reduced after leflunomide treatment (baseline 43 (10) pg/ml; 1 year 29 (7) (p = 0.015), but there was no change in IL6 levels (baseline 158 (41), 1 year 151 (48)). Both IFNgamma and IL6 levels were significantly reduced after methotrexate treatment. This observation was supported by in vitro experiments. The production of IFNgamma by PBL was inhibited by A77-1726, but IL6 production by PBM was not inhibited. CONCLUSION: The differential effect on IFNgamma and IL6 production supports the hypothesis that activated T cells are preferentially inhibited by leflunomide. An explanation may be either inhibition of uridine synthesis or effects on signal transduction pathways.


Assuntos
Artrite Reumatoide/metabolismo , Citocinas/biossíntese , Imunossupressores/farmacologia , Isoxazóis/farmacologia , Metotrexato/farmacologia , Adulto , Idoso , Compostos de Anilina/farmacologia , Antirreumáticos/farmacologia , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/imunologia , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Crotonatos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Seguimentos , Humanos , Hidroxibutiratos/farmacologia , Interferon gama/biossíntese , Interleucina-6/biossíntese , Leflunomida , Pessoa de Meia-Idade , Nitrilas , Toluidinas
16.
J Nucl Med ; 36(6): 975-81, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7769455

RESUMO

UNLABELLED: The aim of this study was to define the clinical feasibility of planar myocardial 18F-fluorodeoxyglucose (FDG) imaging and to assess the relation between 201Tl, FDG and left ventricular function early after myocardial infarction. METHODS: Fifty-one patients were studied 5 +/- 2 days after infarction. Scintigraphic images were visually and quantitatively analyzed using a circumferential profiles technique. FDG uptake was normalized to the area with maximal 201Tl uptake. Scintigraphic data were compared with left ventricular wall motion as assessed by ventriculography in 22 patients. Relative regional 201Tl uptake was categorized as normal (> or = 75% of peak activity), moderately reduced (50%-75%) or severely reduced (< 50%). These tracer defects were considered viable if FDG uptake exceeded 201Tl uptake by > or = 20% and/or if FDG uptake was normal (> or = 75%). All regions with FDG uptake 20% less than 201Tl uptake were considered nonviable. RESULTS: Four hundred forty-one myocardial regions were analyzed; 200 showed normal 201Tl uptake, 241 had reduced uptake, 191 had moderately reduced 201Tl uptake and 50 regions had severely reduced uptake. Viability for moderately and severely reduced regions was observed in 62% and 48%, respectively. A concordance between flow and metabolism was observed in 38% and 52%, respectively. CONCLUSION: Myocardial FDG imaging is feasible with standard gamma camera systems and enables the identification of regions with preserved glucose metabolism in patients shortly after infarction.


Assuntos
Desoxiglucose/análogos & derivados , Radioisótopos de Flúor , Coração/diagnóstico por imagem , Infarto do Miocárdio/diagnóstico por imagem , Angiografia Coronária , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Pessoa de Meia-Idade , Contração Miocárdica , Infarto do Miocárdio/fisiopatologia , Cintilografia , Radioisótopos de Tálio
17.
Int J Rad Appl Instrum B ; 18(1): 59-63, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-2010308

RESUMO

Immunoscintigraphy after submucosal administration of a mixture of 131I-anti-CEA and 131I-anti-CA-19-9 around the tumor in patients with rectal carcinoma may improve pre-operative staging and may contribute to the selection of patients eligible for local treatment. However, visual discrimination of local lymph node metastasis appears unreliable, partly because of scatter from the injection site and substantial diffusion of the radiotracer into the interstitium. Analysis of the diffusion profile, however, may improve the sensitivity and accuracy of this immunoscintigraphic approach.


Assuntos
Anticorpos Antineoplásicos/farmacocinética , Antígenos Glicosídicos Associados a Tumores/imunologia , Antígeno Carcinoembrionário/imunologia , Radioisótopos do Iodo/farmacocinética , Linfonodos/patologia , Neoplasias Retais/patologia , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antineoplásicos/administração & dosagem , Feminino , Humanos , Linfonodos/diagnóstico por imagem , Linfonodos/metabolismo , Masculino , Pessoa de Meia-Idade , Cintilografia , Neoplasias Retais/diagnóstico por imagem , Neoplasias Retais/metabolismo
18.
Endocrinology ; 125(4): 2187-97, 1989 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2791985

RESUMO

The metabolism of T3 by isolated rat hepatocytes was analyzed by Sephadex LH-20 chromatography, HPLC, and RIA for T3 sulfate (T3S) and 3,3'-diiodothyronine (3,3'-T2). Type I iodothyronine deiodinase activity was inhibited with propylthiouracil (PTU), and phenol sulfotransferase activity by SO4(2-) depletion or with competitive substrates or inhibitors. Under normal conditions, labeled T3 glucuronide and I- were the main products of [3'-125I]T3 metabolism. Iodide production was decreased by inhibition (PTU) or saturation (greater than 100 nM T3) of type I deiodinase, which was accompanied by the accumulation of T3S and 3,3'-T2S. Inhibition of phenol sulfotransferase resulted in decreased iodide production, which was associated with an accumulation of 3,3'-T2 and 3,3'-T2 glucuronide, independent of PTU. Formation of 3,3'-T2 and its conjugates was only observed at T3 substrate concentrations below 10 nM. Thus, T3 is metabolized in rat liver cells by three quantitatively important pathways: glucuronidation, sulfation, and direct inner ring deiodination. Whereas T3 glucuronide is not further metabolized in the cultures, T3S is rapidly deiodinated by the type I enzyme. As confirmed by incubations with isolated rat liver microsomes, direct inner ring deiodination of T3 is largely mediated by a low Km, PTU-insensitive, type III-like iodothyronine deiodinase, and production of 3,3'-T2 is only observed if its rapid sulfation is prevented.


Assuntos
Fígado/metabolismo , Tri-Iodotironina/metabolismo , Animais , Cromatografia , Cromatografia Líquida de Alta Pressão , Di-Iodotironinas/farmacologia , Galactosamina/farmacologia , Fígado/citologia , Microssomos Hepáticos/metabolismo , Nitrofenóis/farmacologia , Concentração Osmolar , Pentaclorofenol/farmacologia , Radioimunoensaio , Ratos , Salicilamidas/farmacologia , Sulfatos/farmacologia , Tri-Iodotironina/farmacologia
19.
J Immunoassay ; 9(2): 125-34, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3372702

RESUMO

This paper is the first description of a radioimmunoassay (RIA) for triiodothyronine sulfate (T3S). Rabbits were immunized against T3S coupled to bovine serum albumin using carbodiimide. All animals produced antibodies to T3S but also even higher titers of T3 antibodies. Ka values for binding of T3 and T3S to these antisera varied between 2 x 10(10) and 8 x 10(10) M-1. One of the antisera (#8193) was selected for use in the T3S RIA because of a high titer of T3S antibodies (final dilution 1:50,000), a high sensitivity to T3S (less than 2.5 fmol/tube), and a low crossreactivity by T3 (0.4%). This RIA provides a tool for the study of the importance of sulfation as a metabolic pathway for T3.


Assuntos
Radioimunoensaio , Tri-Iodotironina/análogos & derivados , Afinidade de Anticorpos , Especificidade de Anticorpos , Ligação Competitiva , Reações Cruzadas , Tri-Iodotironina/análise , Tri-Iodotironina/imunologia
20.
J Clin Invest ; 79(6): 1740-8, 1987 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-3584467

RESUMO

Reverse triiodothyronine (rT3) is metabolized predominantly by outer ring deiodination to 3,3'-diiodothyronine (3,3'-T2) in the liver. Metabolism of rT3 and 3,3'-T2 by isolated rat hepatocytes was analyzed by Sephadex LH-20 chromatography, high performance liquid chromatography, and radioimmunoassay, with closely agreeing results. Deiodinase activity was inhibited with propylthiouracil (PTU) and sulfotransferase activity by sulfate depletion or addition of salicylamide or dichloronitrophenol. Normally, little 3,3'-T2 production from rT3 was observed, and 125I- was the main product of both 3,[3'-125I]T2 and [3',5'-125I]rT3. PTU inhibited rT3 metabolism but did not affect 3,3'-T2 clearance as explained by accumulation of 3,3'-T2 sulfate. Inhibition of sulfation did not affect rT3 clearance but 3,3'-T2 metabolism was greatly diminished. The decrease in I- formation from rT3 was compensated by an increased recovery of 3,3'-T2 up to 70% of rT3 metabolized. In conclusion, significant production of 3,3'-T2 from rT3 by rat hepatocytes is only observed if further sulfation is inhibited.


Assuntos
Fígado/metabolismo , Tri-Iodotironina Reversa/metabolismo , Animais , Células Cultivadas , Di-Iodotironinas/biossíntese , Iodeto Peroxidase/metabolismo , Fígado/efeitos dos fármacos , Nitrofenóis/farmacologia , Ratos , Salicilamidas/farmacologia , Sulfatos/metabolismo
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