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1.
J Hum Hypertens ; 23(1): 33-9, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18650837

RESUMO

This cross-sectional analysis of a population-based cohort investigates the postural changes in blood pressure (BP) and heart rate and assesses the prevalence of orthostatic hypotension (OH) and its associations with the medicines used by an elderly population. The study population (n=1000) was a random sample of persons aged 75 years or older in the City of Kuopio, Finland. In 2004, altogether, 781 persons participated in the study. After the exclusion of persons living in institutional care (n=82) and those without orthostatic test (n=46), the final study population comprised 653 home-dwelling elderly persons. OH was defined as a > or =20 mm Hg drop of systolic BP or a > or =10 mm Hg drop of diastolic BP or both 1 or 3 min after standing up from supine position. Systolic BP dropped for more than half of the home-dwelling elderly when they stood up from a supine to a standing position. The total prevalence of OH was 34% (n=220). No significant gender or age differences were seen. The prevalence of OH was related to the total number of medicines in regular use (P<0.05). OH and postural changes in BP are more common among the home-dwelling elderly than reported in previous studies. The prevalence of OH is related to the number of medicines in regular use. There is an obvious need to measure orthostatic BP of elderly persons, as low BP and OH are important risk factors especially among the frail elderly persons.


Assuntos
Pressão Sanguínea/fisiologia , Hipotensão Ortostática/epidemiologia , Hipotensão Ortostática/fisiopatologia , Postura/fisiologia , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Finlândia/epidemiologia , Idoso Fragilizado , Frequência Cardíaca/fisiologia , Humanos , Masculino , Prevalência
2.
Cardiovasc Res ; 20(9): 698-704, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2431781

RESUMO

The two standard methods of computation of the time constant of the isovolumic single exponential decay of the left ventricular pressure were compared in anaesthetised, artificially ventilated, closed chest dogs in 87 experiments. In 23 additional experiments, carried out under basal steady state conditions, the time constant attained a mean (SD) value of 32(5) ms when computed according to the method with zero pressure asymptote assumption (Tz) and 39(7) ms when estimated according to a fit with variable pressure asymptote (Tv). Phenylephrine infusion significantly prolonged Tz from 31(6) to 46(12) and Tv from 39(7) to 92(52) ms. The increase in Tv was significantly greater than that in Tz. Propranolol increased Tv by 50% but Tz remained unaltered. Isoproterenol significantly decreased Tz from 33(2) to 18(3) and Tv from 38(3) to 29(3) ms. The decrease in Tz was significantly greater than that in Tv. Calcium chloride and atrial pacing decreased time constants, but volume loading by dextran infusion did not affect them. With regard to the whole material, the linear regression analysis yielded 0.776 as the coefficient of correlation between Tz and Tv. The two methods of time constant calculation appeared to diverge significantly always when changes in afterload or sympathetic activity were involved. These results indicate the dependence of relaxation on afterload but the independence on preload or ejection timing. In the light of these results the zero pressure asymptote method is recommended for the time constant computation as the practical choice when relaxation of the intact left ventricle is assessed.


Assuntos
Modelos Biológicos , Contração Miocárdica , Animais , Cloreto de Cálcio/farmacologia , Estimulação Cardíaca Artificial , Dextranos/farmacologia , Cães , Feminino , Hemodinâmica , Isoproterenol/farmacologia , Masculino , Contração Miocárdica/efeitos dos fármacos , Fenilefrina/farmacologia , Propranolol/farmacologia , Fatores de Tempo
3.
FEBS Lett ; 297(1-2): 29-33, 1992 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-1551432

RESUMO

We have recently shown that during in vivo photoinhibition the D1 protein is degraded via a modified form, designated D1*. Depending on light conditions, the amount of D1* varies in leaves between 0 and 50% of total D1 content. By isolating thylakoids from leaves acclimated to different light levels, and performing photoinhibition experiments on these thylakoids, the following results on D1 protein degradation were obtained: (i) the protease involved in D1 degradation requires activation by light; (ii) neither acceptor nor donor side photoinhibition of PSII induces formation of D1* in vitro; (iii) in isolated thylakoids, the transformation of D1 to D1* can be induced in low light in the presence of ATP, which suggests that D1* is a phosphorylated form of the D1 protein; (iv) D1*, induced either in vivo or in vitro, is much less susceptible to degradation during illumination of isolated thylakoids than the original D1 protein. We suggest that the modification to D1* is a means to prevent disassembly of photodamaged photosystem II complex in appressed membranes.


Assuntos
Trifosfato de Adenosina/metabolismo , Luz , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Proteínas de Plantas/metabolismo , Western Blotting , Elétrons , Eletroforese em Gel de Poliacrilamida , Membranas Intracelulares/metabolismo , Complexo de Proteína do Fotossistema II
4.
FEBS Lett ; 290(1-2): 153-6, 1991 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-1915868

RESUMO

Illumination of intact pumpkin leaves with high light led to severe photoinhibition of photosystem II with no net degradation of the D1 protein. Instead, however, a modified form of D1 protein with slightly slower electrophoretic mobility was induced with corresponding loss in the original form of the D1 protein. When the leaves were illuminated in the presence of chloramphenicol the modified form was degraded, which led to a decrease in the total amount of the D1 protein. Subfractionation of the thylakoid membranes further supported the conclusion that the novel form of the D1 protein was not a precursor but a high-light modified form that was subsequently degraded.


Assuntos
Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Western Blotting , Cloroplastos/metabolismo , Luz , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Complexo de Proteínas do Centro de Reação Fotossintética/imunologia , Complexo de Proteína do Fotossistema II , Plantas
5.
FEBS Lett ; 455(1-2): 45-8, 1999 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-10428469

RESUMO

In capping cellular mRNAs, a covalent GMP-enzyme intermediate leads to formation of G(5')ppp(5')N at the 5' end of the RNA, which is modified by methylation catalyzed by guanine-7-methyltransferase. Here we show that isolated membranes from tobacco mosaic virus (TMV)-infected plant or insect cells expressing TMV replicase protein p126, synthesized m7GTP using S-adenosylmethionine (AdoMet) as the methyl donor, and catalyzed the formation of a covalent guanylate-p126 complex in the presence of AdoMet. The methyl group from AdoMet was incorporated into p126, suggesting that the complex consisted of m7GMP-p126. Thus, TMV and alphaviruses, despite their evolutionary distance, share the same virus-specific capping mechanism.


Assuntos
Guanosina Monofosfato/metabolismo , Guanosina Trifosfato/metabolismo , Capuzes de RNA , RNA Viral/genética , Vírus do Mosaico do Tabaco/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Primers do DNA , Insetos , Metilação , Metiltransferases/metabolismo , Dados de Sequência Molecular , Nucleotidiltransferases/metabolismo , Mutação Puntual , RNA Viral/metabolismo , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos
6.
Am J Cardiol ; 69(17): 1442-5, 1992 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-1590234

RESUMO

Forty-seven consecutive patients (mean age 61 +/- 8 years) referred for cardiac catheterization due to moderate to severe aortic (n = 30) or mitral (n = 17) valvular heart disease were examined by technetium-99m isonitrile tomography together with a high-dose dipyridamole infusion (0.7 mg/kg) and handgrip stress. Tomography did not identify coronary artery disease (CAD) in 3 of the 21 patients with angiographically proven disease (sensitivity 86%) and suggested false positive results in 5 of the 26 without the disease (specificity 81% and negative predictive accuracy 88%). No patient without angina pectoris and with negative scintigraphy (n = 14) had angiographically significant (greater than or equal to 50% diameter stenosis) CAD. Overall vessel sensitivity was 63%, and specificity was 92%. The frequency of side effects during the dipyridamole-handgrip test was only 7%. No serious complications occurred during stress tests. Thus, technetium-99m isonitrile tomographic imaging, together with high-dose dipyridamole and handgrip exercise, is a useful noninvasive method in excluding significant CAD in patients with valvular heart disease.


Assuntos
Doença das Coronárias/diagnóstico por imagem , Dipiridamol , Teste de Esforço , Doenças das Valvas Cardíacas/complicações , Nitrilas , Compostos de Organotecnécio , Tomografia Computadorizada de Emissão , Angiografia Coronária , Doença das Coronárias/complicações , Dipiridamol/efeitos adversos , Teste de Esforço/efeitos adversos , Feminino , Doenças das Valvas Cardíacas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Tecnécio Tc 99m Sestamibi
7.
Am J Cardiol ; 68(6): 575-9, 1991 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-1877475

RESUMO

Forty-two patients with known stable coronary artery disease, referred for coronary angiography, were examined with technetium-99m-hexakis-2-methoxy-2-methylpropyl-isonitrile (MIBI) tomography combined with a high-dose dipyridamole infusion (0.7 mg/kg) and handgrip stress. MIBI tomography was unable to show coronary artery disease only in 2 patients, thus yielding a sensitivity figure of 95%. MIBI tomography correctly identified 27 (82%) of 33 stenotic lesions (greater than or equal to 50% diameter stenosis) of the left anterior descending artery, 17 (61%) of 28 of those of the left circumflex artery, and 28 (90%) of 31 of those of the right coronary artery. The overall vessel sensitivity was 78%. The computed lumen diameter stenoses were more advanced in cases detected than in those not detected with MIBI tomography: 87 +/- 14 vs 76 +/- 14% (p less than 0.01). The 50 to 69% stenoses did not show any tendency to produce less positive findings than those with greater than or equal to 70% stenoses. In the subgroup of 21 patients who also presented for thallium scintigraphy, the overall diseased vessel identification rate was 76% for thallium tomography and 83% for MIBI tomography (p = not significant). Minor noncardiac side effects related to the dipyridamole-handgrip test occurred only in 5% of 63 study sessions. A high-dose dipyridamole combined with isometric exercise is a safe stress method, and when used during scintigraphy, MIBI tomography is at least as efficient a tool as thallium tomography in detecting diseased vessel territories in patients in coronary artery disease.


Assuntos
Meios de Contraste , Doença das Coronárias/diagnóstico , Dipiridamol , Mãos/fisiologia , Nitrilas , Compostos de Organotecnécio , Esforço Físico/fisiologia , Radioisótopos de Tálio , Idoso , Angiografia , Doença das Coronárias/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Feminino , Humanos , Contração Isométrica/fisiologia , Masculino , Pessoa de Meia-Idade , Tecnécio Tc 99m Sestamibi , Tomografia Computadorizada de Emissão
8.
Am J Cardiol ; 80(3): 273-7, 1997 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-9264418

RESUMO

Myocardial infarction damages sympathetic nerve fibers coursing through the infarct zone. In this study we investigated whether coronary artery disease without myocardial infarction results in sympathetic denervation. We examined 12 patients without a history of previous myocardial infarction and 19 postinfarction patients. 1-123 metaiodobenzylguanidine (MIBG) and technetium-99m sestamibi (MIBI) single-photon emission tomography were conducted at rest to determine the extent of denervated myocardium and the extent of myocardium with reduced perfusion, respectively. In addition, myocardial perfusion during exercise was assessed with MIBI. A MIBG or MIBI defect was determined as being regional uptake of < or =30% of the maximal myocardial activity. All but 1 patient without previous infarction had MIBG defects. MIBG defects (10.3 +/- 8.5% of left ventricular mass) were significantly larger than MIBI defects at rest (2.4 +/- 3.2%, p <0.001) and during exercise (4.8 +/- 6.1%, p <0.05). In multiregression analysis, the size of an MIBG defect was associated with severity of coronary stenoses (> or =90% of lumen diameter; p <0.05), but not with age, number of significant stenoses (> or =50% of lumen diameter), left main disease, functional class, left ventricular ejection fraction, angina pectoris, maximal ST depression, or mean workload during exercise test. MIBG and MIBI defects were significantly larger in patients with severe coronary stenoses than in patients with moderate stenoses (50% to 89% of lumen diameter) (16.4 +/- 8.9% vs 6.0 +/- 5.2% [p <0.05] and 5.0 +/- 3.1% vs 0.6 +/- 1.3% [p <0.001], respectively). The size of MIBG (16.1 +/- 8.9%) and MIBI defects (7.3 +/- 6.5%) at rest in postinfarction patients did not differ from patients with severe stenoses. Our study demonstrates that cardiac adrenergic tissue is very sensitive to ischemia and that regional cardiac sympathetic denervation can occur in patients with stable coronary artery disease without previous myocardial infarction.


Assuntos
Doença das Coronárias/patologia , Coração/inervação , Sistema Nervoso Simpático/patologia , Adulto , Idoso , Doença das Coronárias/fisiopatologia , Teste de Esforço , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio/patologia , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Sestamibi , Tomografia Computadorizada de Emissão de Fóton Único
9.
Am J Cardiol ; 73(12): 865-7, 1994 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-8184809

RESUMO

The effects of enalapril therapy on radionuclide ejection fraction and plasma N-terminal atrial natriuretic peptide were investigated in a randomized, double-blind, placebo-controlled study of 52 patients with acute myocardial infarction. The medication was begun intravenously within 24 hours of the onset of symptoms. At discharge and the end point of 6 months, the radiographic size of the heart was significantly smaller in patients receiving (n = 28) than in those not receiving (n = 24) enalapril therapy (p < 0.03 vs < 0.01). However, left ventricular ejection fraction decreased simultaneously from 50 +/- 10% to 47 +/- 11% in patients treated with enalapril, whereas it increased from 48 +/- 13% to 50 +/- 14% in control patients (p < 0.05 for the difference of the changes). The decrease in ejection fraction was most marked in the infarct-related region of the left ventricle (p < 0.01). During the in-hospital period, plasma N-terminal atrial natriuretic peptide was decreased in patients treated with enalapril, whereas it was increased in those treated with placebo with complicated acute myocardial infarction (p < 0.05). During the following 6 months, the differences remained insignificant. Early administration of enalapril significantly attenuated heart enlargement after myocardial infarction and probably improved hemodynamics during the acute phase of complicated infarction. The decrease in ejection fraction during recovery indicates an impairment of systolic function. The decrease in infarct-related regional ejection fraction suggests that the impairment may be due to poor healing of the infarction scar.


Assuntos
Fator Natriurético Atrial/sangue , Enalapril/uso terapêutico , Infarto do Miocárdio/tratamento farmacológico , Volume Sistólico/efeitos dos fármacos , Função Ventricular Esquerda/efeitos dos fármacos , Idoso , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ventriculografia com Radionuclídeos , Fatores de Tempo
10.
Intensive Care Med ; 15(2): 111-5, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2715498

RESUMO

The haemodynamic effects in the early phase of canine acute experimental pancreatitis (AP) were studied using a cardiac catheterization technique. AP was induced in anaesthetized dogs with an infusion of trypsin-sodium-taurocholate into the pancreatic duct. The initial haemodynamic measurements were performed after the preparation of the animal and 5 min after the induction of AP. Thereafter, pressure and volume parameters were measured at 10 min intervals. AP induced significant increases in heart rate, dP/dtmax and mean arterial pressure, but a decrease in Vmax 5 min after the induction of AP. After the initial phase, the heart rate remained significantly increased, while constant and significant decreases of stroke volume, cardiac output, end-diastolic volume and end-diastolic pressure developed. The parameters of the contractility of the left ventricle were not affected to the same extent. It is suggested that the circulatory failure observed in AP, characterised by a prompt reduction of cardiac output, was primarily due to a heavy reduction in preload. This supports the theory that cardiac output is primarily affected by impaired venous return with consequently decreased preload rather than by a loss of ventricular contractility. Hence, the existence of a myocardial depressant factor in the early phase of experimental AP does not gain support from the present results.


Assuntos
Hemodinâmica , Pancreatite/fisiopatologia , Choque Cardiogênico/etiologia , Doença Aguda , Animais , Cães , Fator Depressor Miocárdico/fisiologia , Pancreatite/complicações , Choque Cardiogênico/fisiopatologia
11.
Int J Cardiol ; 9(2): 161-71, 1985 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2414235

RESUMO

A computer method was developed for the determination of electromechanical delay defined as the time between the onset of Q-wave and the onset of the left ventricular systolic pressure rise. It was validated for heart catheterization studies on 56 intact anaesthetized beagle dogs in 86 sessions. The mean basal value of the electromechanical delay was 22 +/- 4 msec. Heart rate, contractility, preload and afterload were changed by atrial pacing and by infusions of calcium chloride, isoproterenol, propranolol, dextran and phenylephrine. Increase of heart rate by pacing from the spontaneous rate of 90 per min to 240 per min prolonged the electromechanical delay from 21 +/- 5 to 33 +/- 14 msec (P less than 0.001). Otherwise the duration of electromechanical delay changed independently of the heart rate. If it changed, the direction of the change followed that of the pre-ejection period. Its proportion of the pre-ejection period varied from 26 to 52%. The electromechanical delay shortened when a positive inotropic effect was noticed or the presystolic fibre length increased.


Assuntos
Computadores , Eletrocardiografia/instrumentação , Sistema de Condução Cardíaco/fisiologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Cloreto de Cálcio/farmacologia , Débito Cardíaco/efeitos dos fármacos , Estimulação Cardíaca Artificial , Dextranos/farmacologia , Cães , Isoproterenol/farmacologia , Contração Miocárdica/efeitos dos fármacos , Sistemas On-Line/instrumentação , Fenilefrina/farmacologia , Propranolol/farmacologia , Sístole/efeitos dos fármacos , Função Ventricular
12.
Eur J Cardiothorac Surg ; 22(6): 939-43, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12467817

RESUMO

OBJECTIVE: We prospectively tested the hypothesis that atrial enlargement and increased level of atrial natriuretic peptide, N-terminal atrial natriuretic peptide and brain natriuretic peptide would predict atrial fibrillation after coronary artery bypass grafting. METHODS: Eighty-eight elective coronary artery bypass grafting patients had preoperative echocardiographic assessment. The level of atrial natriuretic peptide, N-terminal atrial natriuretic peptide and brain natriuretic peptide were measured preoperatively. Patients were ECG- monitored during the whole hospital stay. RESULTS: Thirty one (35.2%) patients had postoperative atrial fibrillation. In univariate analysis increased age (P=0.003), enlargement of left and right atria (P=0.002 and P=0.004, respectively) and increased level of preoperative atrial natriuretic peptide and N-terminal atrial natriuretic peptide (P=0.016 and P=0.03, respectively) were associated with postoperative atrial fibrillation. There was correlation between the age and level of N-terminal atrial natriuretic peptide (r=0.45 and P<0.001). In multivariate analysis only age and the left atrial enlargement were independent predictors of postoperative atrial fibrillation (P=0.02 and P=0.01). CONCLUSION: Left atrial enlargement was independent predictor for postoperative atrial fibrillation. However, atrial peptides were associated with age and did not independently predict postoperative atrial fibrillation. In addition, the wide variation of the peptide levels renders the implementation of this measure in clinical practice superfluous.


Assuntos
Fibrilação Atrial/etiologia , Fator Natriurético Atrial/sangue , Ponte de Artéria Coronária/efeitos adversos , Doença das Coronárias/cirurgia , Fatores Etários , Idoso , Fibrilação Atrial/sangue , Biomarcadores/sangue , Doença das Coronárias/sangue , Doença das Coronárias/patologia , Feminino , Átrios do Coração/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Peptídeo Natriurético Encefálico/sangue , Prognóstico , Estudos Prospectivos , Precursores de Proteínas/sangue , Fatores de Risco
13.
Water Res ; 36(16): 4079-87, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12405416

RESUMO

The slow leaching of nitrogen from solid waste in landfills, resulting in high concentrations of ammonia in the landfill leachate, may last for several decades. The removal of nitrogen from leachate is desirable as nitrogen can trigger eutrophication in lakes and rivers. In the present study, a low-cost nitrification-denitrification process was developed to reduce nitrogen load especially in leachates from small landfills. Nitrification was studied in laboratory and on-site pilot aerobic biofilters with waste materials as filter media (crushed brick in upflow filters and bulking agent of compost in a downflow filter) while denitrification was studied in a laboratory anoxic/anaerobic column filled with landfill waste. In the laboratory nitrification filters, start-up of nitrification took less than 3 weeks and over 90% nitrification of leachate (NH4-N between 60 and 170mg N l(-1), COD between 230 and 1,300 mg l(-1)) was obtained with loading rates between 100 and 130 mgNH4-N l(-1) d at 25 degrees C. In an on-site pilot study a level of nitrification of leachate (NH4-N between 160 and 270 mg N l(-1), COD between 1,300 and 1,600 mg l(-1)) above 90% was achieved in a crushed brick biofilter with a loading rate of 50mg NH4-N l(-1) d even at temperatures as low as 5-10 degrees C. Ammonium concentrations in all biofilter effluents were usually below the detection limit. In the denitrification column. denitrification started within 2 weeks and total oxidised nitrogen in nitrified leachate (TON between 50 and 150mg N l(-1)) usually declined below the detection limit at 25 degrees C, whereas some ammonium, probably originating from the landfill waste used in the column, was detected in the effluent. No adverse effect was observed on the methanation of waste in the denitrification column with a loading rate of 3.8 g TON-N/t-TS(waste) d. In conclusion, nitrification in a low-cost biofilter followed by denitrification in a landfill body appears applicable for the removal of nitrogen in landfill leachate in colder climates.


Assuntos
Nitrogênio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/economia , Purificação da Água/métodos , Biofilmes , Cromatografia , Custos e Análise de Custo , Filtração , Concentração de Íons de Hidrogênio , Fatores de Tempo
14.
Nuklearmedizin ; 19(5): 239-43, 1980.
Artigo em Inglês | MEDLINE | ID: mdl-7465436

RESUMO

The pulmonary vessels are the first target of tobacco smoke in the circulatory system, but the functional changes occurring in the pulmonary circulation are poorly understood. Hence 46 volunteers were studied by radiocardiography under the following conditions: 1. At rest before and after smoking 2 cigarettes (15 men); 2. After repeated ergometer exercise (5 min, 100 W) with and without smoking (13 men); and 3. Control experiments under the corresponding conditions without smoking (18 subjects). A significant increase occurred in heart rate, cardiac output and systolic arterial blood pressure after smoking when at rest, but an almost significant decrease in pulmonary dispersion volume , whereas the heart rate and pulmonary capillary pressure attained significantly higher values after than before smoking in the exercise tests, with a significant decrease observed in stroke volume, pulmonary blood volume and pulmonary dispersion volume. It is concluded that smoking impairs physical performance, increases pulmonary capillary pressure and reduces pulmonary blood volume and probably the number of open capillaries.


Assuntos
Circulação Sanguínea/efeitos dos fármacos , Nicotina/farmacologia , Fumar , Adulto , Pressão Sanguínea/efeitos dos fármacos , Volume Sanguíneo/efeitos dos fármacos , Débito Cardíaco/efeitos dos fármacos , Coração/diagnóstico por imagem , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Esforço Físico , Cintilografia , Descanso
15.
Water Res ; 35(12): 2913-22, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11471691

RESUMO

The integrated Monod and Haldane models were used to evaluate the kinetic coefficients and their standard deviations using the methane accumulation curves of low-temperature acetoclastic methanogenesis. The linear and exponential approximations and the limitations of their applicability were deduced from the integrated models. The samples of lake sediments and biomass taken from a low-temperature upflow anaerobic sludge blanket (UASB) reactor were used as inoculum in batch assays for acetate methanation. In comparison, the Monod and Haldane models were applied to evaluate the kinetic coefficients for mesophilic acetoclastic methanogenesis accomplished by the pure culture of Methanosarcina barkeri strain MS. The Monod and Haldane models and their approximations were fitted by using non-linear regression. For the wide range of initial acetateconcentrations (4.2-84 mM: 5-100 mM) applied to the UASB biomass at 11 and 22 degrees C and for the lake sediment samples at 6 and 15 degrees C, a better fit was obtained with the Haldane models and their exponential approximations, respectively. For the lake sediments the values of inhibition coefficients decreased at decreasing temperatures. At the highest temperature of 30 degrees C no difference was found between the Haldane and Monod models and the simpler Monod model should be preferred. The values of the maximum growth rate of biomass were highest at 30 degrees C (lake sediment) and 22 degrees C (the UASB biomass) being in a range presented in the literature for mesophilic acetoclastic methanogenesis.


Assuntos
Metano/metabolismo , Methanosarcina barkeri/metabolismo , Acetatos/química , Algoritmos , Anaerobiose , Biomassa , Reatores Biológicos , Temperatura Baixa , Água Doce/química , Água Doce/microbiologia , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Temperatura Alta , Cinética , Methanosarcina barkeri/crescimento & desenvolvimento , Modelos Biológicos , Modelos Estatísticos , Esgotos/química , Esgotos/microbiologia
16.
Alcohol ; 9(2): 149-53, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1599626

RESUMO

The acute dose-related effects of small to moderate doses of ethanol on right ventricular functioning were studied on 18 anesthetized, artificially ventilated dogs in 39 sessions. Diluted ethanol (from 25-37.5%) was infused during 40 minutes, yielding total doses of 1.0 g/kg (n = 15), and 1.5 g/kg (n = 12) with corresponding venous blood ethanol peak concentrations of 1.38 +/- 0.25 and 2.41 +/- 0.31 mg/ml, respectively. Heart rate increased up to 16% in groups receiving ethanol. In the control group receiving the equivalent volume of saline (n = 12) heart rate decreased 14%. Pulmonary arterial systolic pressure increased from 24 +/- 3 to 27 +/- 3 mmHg and diastolic pressure from 11 +/- 2 to 14 +/- 4 mmHg (p less than 0.05) when the ethanol dose was 1.0 g/kg. The pulmonary arterial resistance increased from 620 +/- 135 to 805 +/- 185 dyn.s.cm-5 (p less than 0.01). The peak dP/dt decreased maximally by 20% with increasing ethanol doses. Stroke volume decreased maximally by 14% but due to the increase in heart rate, cardiac output even increased. The changes in end-diastolic volume and pressure were not significant. Hence, the ethanol increased heart rate and afterload of the right ventricle but depressed the myocardium.


Assuntos
Etanol/farmacologia , Função Ventricular Direita/efeitos dos fármacos , Animais , Pressão Sanguínea/efeitos dos fármacos , Débito Cardíaco/efeitos dos fármacos , Cães , Relação Dose-Resposta a Droga , Etanol/administração & dosagem , Etanol/sangue , Frequência Cardíaca/efeitos dos fármacos , Artéria Pulmonar/fisiologia , Volume Sistólico/efeitos dos fármacos , Resistência Vascular/efeitos dos fármacos
17.
Alcohol ; 11(5): 351-4, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7818790

RESUMO

The acute effects of ethanol (1.0 g/kg and 1.5 g/kg, n = 4 and n = 5, yielding blood concentrations of 1.3 +/- 0.2 mg/ml and 2.4 +/- 0.3 mg/ml) on myocardial perfusion were studied in anesthetized, thoracotomized, artificially ventilated dogs by using a radioactive microsphere technique. The control group (n = 5) received saline. The smaller dose of ethanol decreased perfusion in the left ventricular myocardium from 0.737 +/- 0.122 to 0.555 +/- 0.122 ml/g/min (NS), whereas the greater dose nonsignificantly increased it, from 0.744 +/- 0.115 to 0.819 +/- 0.119 ml/g/min (p < 0.01 between the groups). These changes were most evident in subendocardial layers (p < 0.01 both within the groups and between the groups). The greater dose of ethanol increased systemic vascular resistance (p < 0.01 when compared to the control group). The changes in right ventricular myocardium were insignificant. The acute effect of ethanol on coronary blood flow is dose-dependent with small to moderate doses reducing demand for left ventricular flow but with increasing doses evoking not only an increase in demand for flow but also an increase in flow.


Assuntos
Circulação Coronária/efeitos dos fármacos , Etanol/administração & dosagem , Animais , Velocidade do Fluxo Sanguíneo , Cães , Relação Dose-Resposta a Droga , Etanol/farmacologia , Hemodinâmica/efeitos dos fármacos , Microesferas , Resistência Vascular/efeitos dos fármacos , Função Ventricular Esquerda/efeitos dos fármacos
18.
Chemosphere ; 46(6): 851-8, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11922065

RESUMO

Physical-chemical methods have been suggested for the treatment of low strength municipal landfill leachates. Therefore, applicability of nanofiltration and air stripping were screened in laboratory-scale for the removal of organic matter, ammonia, and toxicity from low strength leachates (NH4-N 74-220 mg/l, chemical oxygen demand (COD) 190-920 mg O2/l, EC50 = 2-17% for Raphidocelis subcapitata). Ozonation was studied as well, but with the emphasis on enhancing biodegradability of leachates. Nanofiltration (25 degrees C) removed 52-66% of COD and 27-50% of ammonia, the latter indicating that ammonia may in part have been present as ammonium salt complexes. Biological pretreatment enhanced the overall COD removal. Air stripping (24 h at pH 11) resulted in 89% and 64% ammonia removal at 20 and 6 degrees C, respectively, the stripping rate remaining below 10 mg N/l h. COD removals of 4-21% were obtained in stripping. Ozonation (20 degrees C) increased the concentration of rapidly biodegradable COD (RBCOD), but the proportion of RBCOD of total COD was still below 20% indicating poor biological treatability. The effect of the different treatments on leachate toxicity was assessed with the Daphnia acute toxicity test (Daphnia magna) and algal growth inhibition test (Raphidcocelis subcapitata). None of the methods was effective in toxicity removal. By way of comparison, treatment in a full-scale biological plant decreased leachate toxicity to half of the initial value. Although leachate toxicity significantly correlated with COD and ammonia in untreated and treated leachate, in some stripping and ozonation experiments toxicity was increased in spite of COD and ammonia removals.


Assuntos
Oxidantes Fotoquímicos/química , Ozônio/química , Poluentes do Solo/análise , Poluentes da Água/análise , Purificação da Água/métodos , Amônia , Animais , Fenômenos Químicos , Físico-Química , Daphnia , Filtração , Nitrogênio/análise , Nitrogênio/química , Compostos Orgânicos/análise , Oxigênio/metabolismo , Eliminação de Resíduos , Poluentes do Solo/toxicidade , Testes de Toxicidade , Poluentes da Água/toxicidade
19.
Physiol Meas ; 20(2): 207-14, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10390023

RESUMO

Knowledge of the contributions of transit time heterogeneity to the cardiopulmonary system is important for understanding cardiopulmonary function in patients with intracardiac shunt. We determined the heterogeneity of blood transit times occurring between the right atrium and the left ventricle. Eighty two patients with suspected left-to right shunt were investigated with first-pass 99mTc-labelled red blood cell radiocardiography at supine rest. Forty two of them had a pulmonary-to-systemic flow ratio (Qp:Qs) of less than 1.2 and they served as a control group. The remaining study subjects had a Qp:Qs ratio of 1.7 +/- 0.3 (mean +/- SD). The patients with shunt had significantly greater (p < 0.001) heterogeneity of transit times (49 +/- 9%) than in the controls (39 +/- 7%). Overall heterogeneity of cardiopulmonary transit times in patients with shunt showed a curvature relationship; the highest values were centred in patients with moderate to severe shunt (1.5 < Qp:Qs < 2.5). The results suggest that the increased heterogeneity of transit times mainly occurs within the pulmonary capillary bed in patients with intracardiac shunt. This is probably due to the recruitment of the open capillaries without vessel distension.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Defeitos dos Septos Cardíacos/fisiopatologia , Adolescente , Adulto , Fatores Etários , Idoso , Criança , Pré-Escolar , Feminino , Coração/diagnóstico por imagem , Coração/fisiopatologia , Testes de Função Cardíaca , Humanos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Circulação Pulmonar/fisiologia , Cintilografia , Tecnécio , Fatores de Tempo , Função Ventricular/fisiologia
20.
Water Sci Technol ; 48(4): 37-44, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14531420

RESUMO

The annual production of municipal solid wastes (MSW) in Russia, Finland and Ireland in the late 1990s accounts for 37.5, 2.5 and 2.05 min. tonnes or 252, 488 and 566 kg per capita, respectively. 96.5, 64 and 91% of these wastes (for Russia, Finland and Ireland, correspondingly) are currently disposed of via landfilling. However, nowadays, MSW management in these countries is undergoing drastic changes (source separation, closure of old landfills, reduction of the number of landfills etc.) forced by recent legislation set by the European Union and Russian authorities. This paper evaluates the current status of MSW landfills, as well as information on current leachate and methane emissions in the three above mentioned countries. Landfill leachates are highly variable in each country and between different countries due to different rainfall and climatic conditions and also due to poor landfill top insulation/cover. Leachates in poorly structured landfills are very dilute, whereas leachates with total COD and nitrogen contents as high as 33,700 mg COD/l and 4,030 mg N/l, respectively, have been detected from state-of-the-art sites. Currently, on-site treatment of leachates exists at only a few landfills in Russia, Finland and Ireland but this situation will be considerably improved during the next years. The annual methane emissions from landfills are estimated as 500-900 and 77 ktonnes for Russia and Finland, respectively. Recent estimates from Ireland suggest an annual landfill methane emission of c. 2.1 Mt CO2 equivalent. Several systems of methane recovery have been developed in all three countries and these are currently in different stages of implementation.


Assuntos
Metano/análise , Eliminação de Resíduos , Poluentes da Água/análise , Monitoramento Ambiental , Finlândia , Irlanda , Valores de Referência , Federação Russa
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