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1.
Nephron Clin Pract ; 115(2): c133-41, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20413992

RESUMO

BACKGROUND/AIM: Anemia is associated with increased mortality and morbidity in both early and very late stages of chronic kidney disease (CKD). The aim of this study was to assess whether anemia is a risk factor for mortality or hospitalization in CKD stage 4-5 predialysis patients not yet on dialysis. METHODS: Incident predialysis patients were included between 1999 and 2001 and followed until January 2008 or death. Anemia was defined as mean hemoglobin (Hb) < or =11 g/dl in the 3 months before the start of predialysis. Associations were assessed by Cox regression, linear and logistic regression analysis. RESULTS: A total of 472 patients were included (median follow-up time 12 months, 11% died, 79% started dialysis). Mean Hb was 11.2 g/dl (minimum 7.6, maximum 16.9). Forty-eight percent of patients had anemia at the start of predialysis care. The adjusted mortality risk (hazard ratio, 95% confidence interval) for anemic compared to nonanemic patients was 1.92 (1.04, 3.52). Anemia tended to be related to all-cause but not to non-dialysis-related hospitalization risk. CONCLUSION: At the start of predialysis care, 48% of patients had anemia. Anemia as defined in guideline targets is not associated with an increase in hospitalizations not related to renal replacement therapy, but is likely an important risk factor for mortality in predialysis patients.


Assuntos
Anemia/epidemiologia , Anemia/mortalidade , Hospitalização/tendências , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/mortalidade , Diálise Renal , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida/tendências
2.
Nephrol Dial Transplant ; 24(10): 3183-5, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19383834

RESUMO

BACKGROUND: Self-regulation theory explains how patients' illness perceptions influence self-management behaviour (e.g. via adherence to treatment). Following these assumptions, we explored whether illness perceptions of ESRD-patients are related to mortality rates. METHODS: Illness perceptions of 182 patients participating in the NECOSAD-2 study in the period between December 2004 and June 2005 were assessed. Cox proportional hazard models were used to estimate whether subsequent all-cause mortality could be attributed to illness perception dimensions. RESULTS: One-third of the participants had died at the end of the follow-up. Mortality rates were higher among patients who believed that their treatment was less effective in controlling their disease (perceived treatment control; RR = 0.71, P = 0.028). This effect remained stable after adjusting for sociodemographic and clinical variables (RR = 0.65, P = 0.015). CONCLUSIONS: If we consider risk factors for mortality, we tend to rely on clinical parameters rather than on patients' representations of their illness. Nevertheless, results from the current exploration may suggest that addressing patients' personal beliefs regarding the effectiveness of treatment can provide a powerful tool for predicting and perhaps even enhancing survival.


Assuntos
Falência Renal Crônica/mortalidade , Falência Renal Crônica/psicologia , Idoso , Feminino , Humanos , Masculino , Inquéritos e Questionários
3.
Cardiovasc Res ; 14(3): 142-53, 1980 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7397716

RESUMO

Forces in the myocardial wall can be measured in several ways or calculated using certain simplifying assumptions. In this study we investigated the reliability of two measurement methods, one of which was introduced by Feigl et al (1967), whereas the other method was developed in our laboratory. Both methods were tested in actively contracting skeletal muscle and beating hearts of open-chest dogs by comparing the force transferred from the muscle to the transducer under various circumstances. It appeared that changes in muscle length, be it through initial length changes or through shortening during contractions, had a great influence on the transfer of force to the transducer, for both methods, in both preparations. In the heart a decrease in internal left ventricular diameter of 15% resulted in a 50% reduction of force transferred to the transducer, independent of whether the length took place as a change in filling or as a change in ejection volume. In skeletal muscle the length-dependent effects during shortening were larger and those resulting from initial length changes were more variable than in beating hearts. That the effects of muscle length changes are of such magnitude means that, if no other errors exist, they alone would invalidate that until principally different methods of measuring wall stress in the myocardium are discovered, attempts at accurate calculation of myocardial wall stress are a better approach than wall stress measurements.


Assuntos
Coração/fisiologia , Estresse Mecânico , Animais , Biometria , Cães , Masculino , Contração Muscular , Músculos/fisiologia , Contração Miocárdica , Coelhos , Transdutores
4.
Hypertension ; 12(4): 411-9, 1988 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3169950

RESUMO

In renovascular hypertension adaptive mechanisms in the poststenotic kidney are a probable cause of the 20 to 25% false-negative findings during rapid sequence urography or [123I]o-iodohippurate renography. We blocked the renin-angiotensin system in an effort to increase the yield of these diagnostic procedures. Chronically instrumented, salt-depleted conscious dogs were used in which a light (n = 5), moderate (n = 4), or severe (n = 2) renal artery stenosis was induced. Before stenosis 10 of the dogs showed no left-right differences with either diagnostic procedure, and angiotensin converting enzyme (ACE) inhibition did not change this result. Two to 3 weeks after induction of a renal artery stenosis, all dogs showed signs of renovascular hypertension. However, only 50% of the renograms and 22% of the urograms showed differences between the two kidneys indicative of the presence of stenosis. After ACE inhibition, all previously negative test results became positive (abnormal) and previously existing left-right differences became more evidence. Electromagnetically measured renal blood flow on the stenotic side did not change during ACE inhibition (146 +/- 13 vs 145 +/- 21 ml/min), whereas contralateral blood flow showed a distinct increase (207 +/- 18 vs 282 +/- 20 ml/min, p less than 0.01). In conclusion, ACE inhibition markedly improves the sensitivity of rapid sequence urography and hippurate renography in the diagnosis of renovascular hypertension in the two-kidney, one clip Goldblatt hypertensive dog. The effects of ACE inhibition on the handling of the different tracers do not appear to be related to its effects on renal blood flow or systemic blood pressure.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Hipertensão Renovascular/diagnóstico por imagem , Animais , Pressão Sanguínea/efeitos dos fármacos , Cães , Hipertensão Renovascular/fisiopatologia , Masculino , Renografia por Radioisótopo , Obstrução da Artéria Renal/fisiopatologia , Circulação Renal/efeitos dos fármacos , Urografia
5.
J Nucl Med ; 37(3): 482-8, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8772652

RESUMO

UNLABELLED: We studied the mechanism of angiotensin-converting enzyme (ACE) inhibition-induced changes in hippurate renography of the poststenotic kidney. METHODS: Ten male mongrel dogs, six with unilateral and four with bilateral renal artery stenosis, were equipped with renal artery blood flow probes and catheters in the aorta, atrium and both renal veins. RESULTS: Enalaprilat (10 mg intravenously) in conscious dogs with renal artery stenoses produced changes in all stenotic (n = 11) but not in nonstenotic kidney 123I-hippurate renograms (n = 6). Renographic changes correlated significantly with initiation of intrarenal 131I-hippurate retention, a decrease in mean arterial pressure (MAP), renal extraction of 131I-hippurate and 125I-iothalamate (r = 0.68, r = 0.62, r = 0.84, r = 0.83, respectively) but not with renal blood flow changes (r = 0.34). Furthermore, renal uptake of 131I-hippurate and 125I-iothalamate decreased in stenotic kidneys with a grade II renogram (-52 +/- 11% and -79 +/- 6%, respectively). Iodine-125-hippurate autoradiograms of stenotic kidneys during ACE inhibition showed tracer retention mainly in the proximal tubular cells. Results during osmotic diuresis supported our findings. CONCLUSION: Angiotensin-converting enzyme inhibition-induced hippurate retention curves of poststenotic kidneys appear to result from a sequence of events. A decrease in MAP combined with efferent vasodilation leads to a decrease in intraglomerular capillary pressure. This decrease in pressure causes a decrease in glomerular filtration rate and proximal tubular urine flow. This decrease in turn hampers tubular hippurate transit and transport across the luminal membrane, leading to intrarenal hippurate retention and, in more severe cases, decreased renal hippurate uptake.


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Enalaprilato , Hipertensão Renovascular/diagnóstico por imagem , Radioisótopos do Iodo , Ácido Iodoipúrico , Rim/fisiopatologia , Renografia por Radioisótopo/efeitos dos fármacos , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Autorradiografia , Pressão Sanguínea , Meios de Contraste , Cães , Enalaprilato/farmacologia , Taxa de Filtração Glomerular , Hipertensão Renovascular/fisiopatologia , Ácido Iotalâmico , Rim/efeitos dos fármacos , Masculino , Renografia por Radioisótopo/métodos , Circulação Renal , Fatores de Tempo
6.
Am J Hypertens ; 4(12 Pt 2): 741S-744S, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1777188

RESUMO

The effect of angiotensin converting enzyme (ACE) inhibition on the sensitivity of radionuclide renography in the diagnosis of a unilateral renal artery stenosis was tested both in a conscious dog model and in the human situation. ACE inhibition (10 mg enalaprilic acid, intravenously) markedly improved the sensitivity of [123I]hippuran renography in 10 renovascular hypertensive dogs with a mild to moderate unilateral renal artery stenosis from 50 to 100%. This improved sensitivity was due to an ACE-inhibition-induced delayed tracer handling at the stenotic side without an appreciable change in the renographic curve at the contralateral side. A similar phenomenon was observed in 15 hypertensive patients with an angiographically proved unilateral renal artery stenosis. Both [123I]hippuran and 99mTc-diethylenetriaminepentaacetic acid (DTPA) handling was delayed on the stenotic side after oral enalapril treatment. However, only a moderate increase in sensitivity was observed comparing control renograms to ACE-inhibition renograms: from 87 to 93% for hippuran, and from 60 to 86% for DTPA. Eight of these 15 patients underwent either surgery or angioplasty resulting in a successful correction of the stenosis. Hypertension was more or less cured in five patients. Each of these patients had shown an ACE-inhibition-induced change in the renogram at the stenotic side, suggesting that such a response may predict the curability of the hypertension. However, of the three patients that showed no blood pressure change upon successful revascularization, two showed a positive ACE-inhibition renogram. In conclusion, in an ideal setting as obtained in animal experiments, ACE inhibition improves the sensitivity of renographic studies to 100%. However, its value in the clinical setting needs more standardization.


Assuntos
Renografia por Radioisótopo/métodos , Obstrução da Artéria Renal/diagnóstico por imagem , Teprotida , Animais , Modelos Animais de Doenças , Cães , Humanos , Radioisótopos do Iodo , Ácido Iodoipúrico , Sensibilidade e Especificidade , Pentetato de Tecnécio Tc 99m
7.
Clin Chim Acta ; 179(2): 133-42, 1989 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-2920446

RESUMO

The aim of this study was to establish whether differences in sodium efflux rate constants (ke) in human erythrocytes occur when artificial media are compared with plasma. Using a 22Na tracer method, a mean total ke of 0.49 +/- 0.10 h-1 and significantly (p less than 0.05) lower ke values in Hanks' solution (0.43 +/- 0.08 h-1) and Basic Salt Solution (0.37 +/- 0.07 h-1) were observed. Exhaustive dialysis of plasma against Hanks' solution over a membrane with relative molecular mass cut-off of 1000 Da resulted in a decrease of the plasma total ke value to that measured in Hanks' solution. After equilibrium dialysis of plasma against Hanks' solution a decrease of total ke was found in plasma and an increase of the ke in Hanks' solution was measured. The data suggest the presence of an excess of dialyzable, active sodium transport stimulating plasma factor(s) with relative molecular mass below 1000 Da.


Assuntos
Eritrócitos/metabolismo , Sódio/metabolismo , Adulto , Transporte Biológico Ativo , Glicemia/análise , Eletrólitos/sangue , Furosemida/farmacologia , Humanos , Cinética , Peso Molecular , Ouabaína/farmacologia , Sódio/sangue
8.
Clin Chim Acta ; 213(1-3): 61-73, 1992 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-1477988

RESUMO

The main objective of this study was to further characterize the plasma factor(s) which stimulate sodium efflux from erythrocytes, which we reported previously. Dialysis of plasma against an artificial medium using membranes with varying molecular mass cut-off points revealed relative molecular mass(es) of the factor(s) of 100-1000 Da. The factor(s) could be absorbed on Dowex at pH 1.5 and Amberlite at pH 11.0, indicating 'Zwitterionic' character. They are hydrophilic and resistant to acid hydrolysis. These characteristics and direct measurements of contents made amino acids likely candidates for the efflux stimulating properties of the factor(s). Indeed, plasma amino acids added to artificial medium could abolish the sodium efflux difference between plasma and the artificial medium. The efflux stimulating effect of amino acids appeared not to be the result of sodium influx stimulation. A coincident finding was that plasma also contains dialyzable sodium influx stimulating factor(s) which are not amino acids.


Assuntos
Aminoácidos/sangue , Membrana Eritrocítica/metabolismo , Sódio/sangue , Adulto , Transporte Biológico , Cromatografia , Diálise , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Íons , Peso Molecular , Soluções
9.
Clin Chim Acta ; 225(1): 29-42, 1994 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8033352

RESUMO

A GC-MS determination of urea in serum or spent dialysate is described, using 13C15N2-labelled urea and assaying the area ratio of labelled to natural urea by mass fragmentographic monitoring of fragments m/e 153 and 156, after its eventual conversion into the trimethylsilylether-derivative of 2-hydroxypyrimidine. The procedure can be successfully applied in the follow-up of the disappearance of labelled urea in serum after intravenous injection in man, enabling kinetic parameters of urea to be established, e.g. for purposes of studying the effectiveness of dialysis procedures. Furthermore the method can be used for validation of routine methods for measuring urea in other fluids, in particular dialysate. Examples are given of both applications of the GC-MS method described.


Assuntos
Ureia/análise , Ureia/sangue , Calibragem , Isótopos de Carbono , Diálise , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Marcação por Isótopo , Cinética , Masculino , Pessoa de Meia-Idade , Isótopos de Nitrogênio , Reprodutibilidade dos Testes
10.
Clin Nephrol ; 26(6): 311-3, 1986 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3802598

RESUMO

A 52-year-old man developed minimal change nephrotic syndrome which responded only partially to prednisolone. The addition of cyclophosphamide resulted in a complete remission. During a second episode of nephrotic syndrome prednisolone and cyclophosphamide only gave a partial remission. During a third episode, 42 months after the initial presentation, Hodgkin's disease clinical stage IA was diagnosed. Mantle field radiation therapy was given after which proteinuria gradually decreased to zero in the course of 17 months. The patient has remained free of disease until now (15 months).


Assuntos
Doença de Hodgkin/etiologia , Nefrose Lipoide/complicações , Ciclofosfamida/uso terapêutico , Quimioterapia Combinada , Humanos , Indometacina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Nefrose Lipoide/tratamento farmacológico , Prednisolona/uso terapêutico , Fatores de Tempo
11.
Adv Perit Dial ; 10: 179-82, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7999822

RESUMO

Cefuroxime is a second-generation cephalosporin that can be used for the treatment of peritoneal dialysis-related peritonitis. Cefuroxime-axetil is an orally available pro-drug of cefuroxime. The effect of concomitant use of a phosphate binder on the bioavailability of cefuroxime-axetil was studied in 7 continuous ambulatory peritoneal dialysis (CAPD) patients who had not recently suffered from peritonitis. On two occasions, we measured cefuroxime levels in plasma, peritoneal effluent, and urine for 24 h after the ingestion of 1 g of cefuroxime-axetil: once together with a phosphate binder (+PB) and once without (-PB). Peak plasma concentrations (Cmax) were +PB: 22.7 mg/L (15.3-32.6) (median and range) and -PB: 23.2 mg/L (18.9-27.4). The area under the curve (AUC) of the plasma levels was +PB: 364 mg h/L (247-530) and -PB: 368 mg h/L (296-438). The plasma elimination half-life (t1/2) was +PB: 13.9 h (11.5-14.6) and -PB: 13.8 h (12.2-15.4). Cefuroxime concentrations in the peritoneal effluent from the first exchange were 1.9 mg/L (0.5-6.2) (+PB) and 3.4 mg/L (2.1-4.7) (-PB). In the peritoneal effluent from the second up to the last exchange, the cefuroxime levels were stable at +PB: 5.0 mg/L (2.0-8.8) and -PB: 5.3 mg/L (1.8-7.5). The total amount of cefuroxime excreted into peritoneal effluent and urine was +PB: 82 mg (30-124), -PB: 100 mg (36-129). So Cmax, AUC, t1/2 and the total amount of excreted cefuroxime were not different. Therefore, the bioavailability of cefuroxime-axetil is not reduced by the use of a phosphate binder.


Assuntos
Hidróxido de Alumínio/farmacologia , Cefuroxima/análogos & derivados , Diálise Peritoneal Ambulatorial Contínua , Fosfatos/metabolismo , Pró-Fármacos/farmacocinética , Administração Oral , Hidróxido de Alumínio/administração & dosagem , Disponibilidade Biológica , Cefuroxima/administração & dosagem , Cefuroxima/farmacocinética , Feminino , Humanos , Falência Renal Crônica/metabolismo , Falência Renal Crônica/terapia , Masculino , Pró-Fármacos/administração & dosagem
12.
Ned Tijdschr Geneeskd ; 141(5): 229-33, 1997 Feb 01.
Artigo em Holandês | MEDLINE | ID: mdl-9064539

RESUMO

In the Netherlands, only one third of the patients of 65 years or older with terminal renal failure are currently admitted to dialysis treatment. Dialysis in older patients frequently leads to adequate survival and good subjective quality of life. In other words, age as such is not a contraindication to dialysis. Haemodialysis and peritoneal dialysis have about the same clinical results in older patients, as is the case in younger age groups; the choice depends on patient-linked factors and on the patient's preference. It is to be expected that in a number of years the majority of dialysis patients will be aged 65 years or older.


Assuntos
Comorbidade , Falência Renal Crônica/terapia , Terapia de Substituição Renal , Idoso , Humanos , Falência Renal Crônica/mortalidade , Pessoa de Meia-Idade , Cooperação do Paciente , Diálise Peritoneal , Prognóstico , Qualidade de Vida , Diálise Renal , Fatores de Risco
13.
J Hypertens Suppl ; 6(4): S455-7, 1988 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3241237

RESUMO

We performed experiments in the two-kidney, one clip Goldblatt hypertensive dog to see whether angiotensin converting enzyme (ACE) inhibition could improve the sensitivity of hippurate renography in detecting renal artery stenosis. Ten dogs on a sodium-restricted diet were studied before and after induction of a renal artery stenosis. In the absence of renal artery stenosis nine dogs showed normal renograms before ACE inhibition, and one was false positive. During ACE inhibition all 10 renograms were normal. With a renal artery stenosis 50% of the renograms were false negative, whereas a 100% sensitivity was reached during ACE inhibition. The alterations induced by the ACE inhibition on the renograms were not related to changes in renal blood flow. In conclusion, ACE inhibition markedly improved the sensitivity of hippurate renography in the two-kidney, one clip dog.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Hipertensão Renovascular/diagnóstico por imagem , Animais , Cães , Hipuratos , Masculino , Radiografia , Renografia por Radioisótopo , Fluxo Sanguíneo Regional , Obstrução da Artéria Renal/diagnóstico
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