RESUMO
BACKGROUND: Trial findings show cognitive behaviour therapy (CBT) and graded exercise therapy (GET) can be effective treatments for chronic fatigue syndrome, but patients' organisations have reported that these treatments can be harmful and favour pacing and specialist health care. We aimed to assess effectiveness and safety of all four treatments. METHODS: In our parallel-group randomised trial, patients meeting Oxford criteria for chronic fatigue syndrome were recruited from six secondary-care clinics in the UK and randomly allocated by computer-generated sequence to receive specialist medical care (SMC) alone or with adaptive pacing therapy (APT), CBT, or GET. Primary outcomes were fatigue (measured by Chalder fatigue questionnaire score) and physical function (measured by short form-36 subscale score) up to 52 weeks after randomisation, and safety was assessed primarily by recording all serious adverse events, including serious adverse reactions to trial treatments. Primary outcomes were rated by participants, who were necessarily unmasked to treatment assignment; the statistician was masked to treatment assignment for the analysis of primary outcomes. We used longitudinal regression models to compare SMC alone with other treatments, APT with CBT, and APT with GET. The final analysis included all participants for whom we had data for primary outcomes. This trial is registered at http://isrctn.org, number ISRCTN54285094. FINDINGS: We recruited 641 eligible patients, of whom 160 were assigned to the APT group, 161 to the CBT group, 160 to the GET group, and 160 to the SMC-alone group. Compared with SMC alone, mean fatigue scores at 52 weeks were 3·4 (95% CI 1·8 to 5·0) points lower for CBT (p = 0·0001) and 3·2 (1·7 to 4·8) points lower for GET (p = 0·0003), but did not differ for APT (0·7 [-0·9 to 2·3] points lower; p = 0·38). Compared with SMC alone, mean physical function scores were 7·1 (2·0 to 12·1) points higher for CBT (p = 0·0068) and 9·4 (4·4 to 14·4) points higher for GET (p = 0·0005), but did not differ for APT (3·4 [-1·6 to 8·4] points lower; p=0·18). Compared with APT, CBT and GET were associated with less fatigue (CBT p = 0·0027; GET p = 0·0059) and better physical function (CBT p=0·0002; GET p<0·0001). Subgroup analysis of 427 participants meeting international criteria for chronic fatigue syndrome and 329 participants meeting London criteria for myalgic encephalomyelitis yielded equivalent results. Serious adverse reactions were recorded in two (1%) of 159 participants in the APT group, three (2%) of 161 in the CBT group, two (1%) of 160 in the GET group, and two (1%) of 160 in the SMC-alone group. INTERPRETATION: CBT and GET can safely be added to SMC to moderately improve outcomes for chronic fatigue syndrome, but APT is not an effective addition. FUNDING: UK Medical Research Council, Department of Health for England, Scottish Chief Scientist Office, Department for Work and Pensions.
Assuntos
Adaptação Fisiológica , Terapia Cognitivo-Comportamental , Terapia por Exercício , Síndrome de Fadiga Crônica/terapia , Atividades Cotidianas , Adulto , Terapia por Exercício/efeitos adversos , Síndrome de Fadiga Crônica/fisiopatologia , Feminino , Humanos , Masculino , Especialização , Inquéritos e Questionários , Resultado do TratamentoRESUMO
A case of culture-positive primary cutaneous Mycobacterium tuberculosis infection of the penis was diagnosed in a male patient; 1 year later, endometrial tuberculosis was diagnosed in the patient's wife. These organisms were confirmed to be indistinguishable by use of molecular techniques.
Assuntos
Mycobacterium tuberculosis/isolamento & purificação , Doenças do Pênis/microbiologia , Doenças Bacterianas Sexualmente Transmissíveis/transmissão , Tuberculose Cutânea/transmissão , Doenças Uterinas/microbiologia , DNA Bacteriano/análise , Endométrio/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/genética , Doenças do Pênis/patologia , Doenças Bacterianas Sexualmente Transmissíveis/microbiologia , Tuberculose Cutânea/microbiologia , Tuberculose Cutânea/patologiaRESUMO
The Internet is enabling scientists and clinicians in areas with endemic malaria to transfer information to scientists and clinicians in other countries. This should allow changes in therapy to follow the rapid changes in the disease that have posed such difficulties in the past. This article reviews Internet resources that focus on malaria. This includes 90 Web sites in 12 sections. Authoritative multinational organizational sites and regional sites, such as those in Africa, Asia (including Thailand and India), and South America (in Venezuela and Brazil), are described. Basic research-oriented databases, such as those that deal with plasmodia genomics, biochemistry, and vaccine development, as well as vector information and geographic satellite information systems, are reviewed. There is a section about malaria research-funding organizations that offer online applications. Useful teaching resources and journals, including those with full online access, are detailed.
Assuntos
Internet , Malária , Informática Médica , África , Ásia , Humanos , América do SulRESUMO
AIMS: Experimental studies have suggested that constant intravenous infusion would be preferable to conventional intermittent bolus administration of beta-lactam antibiotics for serious Gram-negative infections. Severe melioidosis (Burkholderia pseudomallei infection) carries a mortality over 40% despite treatment with high dose ceftazidime. The aim of this study was to measure the pharmacokinetic and pharmacodynamic effects of continuous infusion of ceftazidime vs intermittent bolus dosing in septicaemic melioidosis. METHODS: Patients with suspected septicaemic melioidosis were randomised to receive ceftazidime 40 mg kg(-1) 8 hourly by bolus injection or 4 mg kg(-1) h(-1) by constant infusion following a 12 mg kg(-1) priming dose and pharmacokinetic and pharmacodynamic parameters were compared. RESULTS: Of the 34 patients studied 16 (59%) died. Twenty patients had cultures positive for B. pseudomallei of whom 12 (60%) died. The median MIC90 of B. pseudomallei was 2 mg l(-1), giving a minimum target concentration (4*MIC) of 8 mg l(-1). The median (range) estimated total apparent volume of distribution, systemic clearance and terminal elimination half-lives of ceftazidime were 0.468 (0.241-0. 573) l kg(-1), 0.058 (0.005-0.159) l kg(-1) h(-1) and 7.74 (1.95-44.71) h, respectively. Clearance of ceftazidime and creatinine clearance were correlated closely (r = 0.71; P < 0.001) and there was no evidence of significant nonrenal clearance. CONCLUSIONS: Simulations based on these data and the ceftazidime sensitivity of the B. pseudomallei isolates indicated that administration by constant infusion would allow significant dose reduction and cost saving. With conventional 8 h intermittent dosing to patients with normal renal function, plasma ceftazidime concentrations could fall below the target concentration but this would be unlikely with a constant infusion. Correction for renal failure, which is common in patients with meliodosis is Clearance = k(*) creatinine clearance where k = 0.72. Calculation of a loading dose gives median (range) values of loading dose, DL of 18.7 mg kg(-1) (9.5-23) and infusion rate I = 3.5 mg k(-1) h(-1) (0.4-13) (which equals 84 mg kg(-1) day(-1)). A nomogram for adjustment in renal failure is given.
Assuntos
Bacteriemia/tratamento farmacológico , Burkholderia pseudomallei/efeitos dos fármacos , Ceftazidima/administração & dosagem , Cefalosporinas/administração & dosagem , Melioidose/tratamento farmacológico , Adulto , Idoso , Bacteriemia/economia , Bacteriemia/metabolismo , Burkholderia pseudomallei/metabolismo , Ceftazidima/economia , Ceftazidima/farmacocinética , Cefalosporinas/economia , Cefalosporinas/farmacocinética , Feminino , Humanos , Infusões Intravenosas , Modelos Lineares , Masculino , Melioidose/economia , Melioidose/metabolismo , Pessoa de Meia-Idade , Modelos Biológicos , Estatísticas não ParamétricasRESUMO
AIMS: Experimental studies have suggested that constant intravenous infusion would be preferable to conventional intermittent bolus administration of beta-lactam antibiotics for serious Gram-negative infections. Severe melioidosis (Burkholderia pseudomallei infection) carries a mortality of 40% despite treatment with high dose ceftazidime. The aim of this study was to measure the pharmacokinetic and pharmacodynamic effects of continuous infusion of ceftazidime vs intermittent bolus dosing in septicaemic melioidosis. METHODS: Patients with suspected septicaemic melioidosis were randomised to receive ceftazidime 40 mg kg-1 8 hourly by bolus injection or 4 mg kg-1 h-1 by constant infusion following a 12 mg kg-1 priming dose to perform estimation of pharmacokinetic and pharmacodynamic parameters. RESULTS: Of the 34 patients studied 16 (59%) died. Twenty patients had cultures positive for B. pseudomallei of whom 12 (60%) died. The median MIC90 of B. pseudomallei was 2 mg l-1, giving a target concentration CT, of 8 mg l-1. The median (range) estimated total apparent volume of distribution, systemic clearance and terminal elimination half-lives of ceftazidime were 0.468 (0.241-0.573) l kg-1, 0.058 (0.005-0.159) l kg-1 h-1 and 7.74 (1.95-44.71) h, respectively. Clearance of ceftazidime and creatinine clearance were correlated closely (r = 0. 71; P < 0.001) and there was no evidence of significant nonrenal clearance. CONCLUSIONS: Simulations based on these data and the ceftazidime sensitivity of the B. pseudomallei isolates indicated that administration by constant infusion would allow significant dose reduction and cost saving. With conventional 8 h intermittent dosing to patients with normal renal function, plasma ceftazidime concentrations could fall below the target concentration but this would be unlikely with a constant infusion. Correction for renal failure which is common in these patients is Clearance = k * creatinine clearance where k = 0.072. Calculation of a loading dose gives median (range) values of loading dose, DL of 3.7 mg kg-1 (1. 9-4.6) and infusion rate I = 0.46 mg kg h-1 (0.04-1.3) (which equals 14.8 mg kg-1 day-1). A nomogram for adjustment in renal failure is given.
Assuntos
Bacteriemia/tratamento farmacológico , Ceftazidima/administração & dosagem , Melioidose/tratamento farmacológico , Adulto , Idoso , Ceftazidima/farmacocinética , Ceftazidima/farmacologia , Feminino , Humanos , Infusões Intravenosas , Injeções Intravenosas , Masculino , Pessoa de Meia-IdadeRESUMO
Children with severe malaria often present with lactic acidosis and hypoglycemia. Although both complications independently predict mortality, mechanisms underlying their development are poorly understood. To study these metabolic derangements we sequentially allocated 21 children with falciparum malaria and capillary lactate concentrations of 5 mmol/L or more to receive either quinine or artesunate as antimalarial therapy, and dichloroacetate or saline placebo for lactic acidosis. We then administered a primed infusion (90 min) of L-[3-13C1]sodium lactate and D-[6,6-D2]glucose to determine the kinetics of these substrates. The mean (SD) glucose disposal rate in all patients was 56 (16) micromol/kg x min, and the geometric mean (range) lactate disposal rate was 100 (66-177) micromol/kg x min. Glucose and lactate disposal rates were positively correlated (r = 0.62; P = 0.005). Artesunate was associated with faster parasite clearance, lower insulin/glucose ratios, and higher glucose disposal rates than quinine. Lactate disposal was positively correlated with plasma lactate concentrations (r = 0.66; P = 0.002) and time to recovery from coma (r = 0.82; P < 0.001; n = 15). Basal lactate disposal rates increased with dichloroacetate treatment. Elevated glucose turnover in severe malaria mainly results from enhanced anaerobic glycolysis. Quinine differs from artesunate in its effects on glucose kinetics. Increased lactate production is the most important determinant of lactic acidosis.
Assuntos
Artemisininas , Glicemia/metabolismo , Ácido Láctico/sangue , Malária Falciparum/sangue , Acidose Láctica/tratamento farmacológico , Antimaláricos/uso terapêutico , Artesunato , Criança , Pré-Escolar , Ácido Dicloroacético/uso terapêutico , Feminino , Humanos , Lactente , Insulina/sangue , Cinética , Malária Falciparum/tratamento farmacológico , Masculino , Quinina/uso terapêutico , Sesquiterpenos/uso terapêuticoRESUMO
The artemisinin derivatives are now used widely in areas with multidrug-resistant Plasmodium falciparum malaria such as Southeast Asia, but concerns remain over their potential for neurotoxicity. Mice, rats, dogs, and monkeys treated with high doses of intramuscular artemether or arteether develop an unusual pattern of focal damage to brain stem nuclei (particularly those involved in auditory processing). To investigate whether a similar toxic effect occurs in patients treated with these compounds, clinical neurologic evaluation, audiometry and early latency auditory evoked responses were measured in a single-blind comparison of 79 patients who had been treated with > or =2 courses of oral artemether or artesunate within the previous 3 years, and 79 age- and sex-matched controls living in a malaria-endemic area on the northwestern border of Thailand. There were no consistent differences in any of these test results between the cases and controls. This study failed to detect any evidence of significant neurotoxicity in patients treated previously with oral artemether or artesunate for acute malaria.
Assuntos
Antimaláricos/efeitos adversos , Artemisininas , Potenciais Evocados Auditivos do Tronco Encefálico/efeitos dos fármacos , Malária Falciparum/tratamento farmacológico , Sesquiterpenos/efeitos adversos , Adolescente , Adulto , Animais , Antimaláricos/uso terapêutico , Artemeter , Artesunato , Audiometria , Estudos de Casos e Controles , Criança , Pré-Escolar , Resistência a Múltiplos Medicamentos , Quimioterapia Combinada , Feminino , Seguimentos , Humanos , Masculino , Mefloquina/uso terapêutico , Pessoa de Meia-Idade , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/patogenicidade , Sesquiterpenos/uso terapêutico , TailândiaRESUMO
Severe melioidosis is a life-threatening, systemic bacterial infection caused by Burkholderia pseudomallei. A prospective, randomized treatment trial was conducted in northeast Thailand to compare ceftazidime (a penicillin-binding protein [PBP]-3-specific agent that causes release of large amounts of endotoxin in vitro) and imipenem (a PBP-2-specific agent that kills B. pseudomallei more rapidly but releases low amounts of endotoxin) in severe melioidosis over a 6-h time course after the first dose of antibiotic. Despite similar clinical, microbiological, endotoxin, and cytokine measures at study entry, ceftazidime-treated patients (n=34) had significantly greater systemic endotoxin (P<.001) than patients treated with imipenem (n=34) after the first dose of antibiotic. No overall difference in mortality was observed (35% in both groups [95% confidence interval, 20%-50%]). Differential antibiotic-induced endotoxin release is demonstrable in severe melioidosis. These differences in endotoxin release did not appear to have a significant impact on survival in this group of patients.
Assuntos
Antibacterianos/uso terapêutico , Ceftazidima/uso terapêutico , Endotoxinas/metabolismo , Imipenem/uso terapêutico , Melioidose/tratamento farmacológico , Adulto , Idoso , Citocinas/sangue , Feminino , Humanos , Masculino , Melioidose/imunologia , Melioidose/mortalidade , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
Raised serum concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, or IL-10 are associated with mortality in patients with sepsis, but it is not known whether elevated cytokine levels are independently predictive of mortality. Cytokine assays (TNF-alpha, IL-6, and IL-10) were performed on admission plasma samples from 172 adult Thai patients with severe melioidosis. Mortality was 31.4%. APACHE II score; septicemia; plasma lactate; TNF-alpha, IL-6, and IL-10 concentrations; and IL-10/TNF-alpha and IL-6/IL-10 ratios were each associated with outcome (P=.001 for all variables). Only the APACHE II score and either IL-6 or IL-10 concentration were independent predictors of mortality, as determined by use of multiple logistic regression (with cytokine concentrations and ratios entered separately). In a multivariate analysis, including both IL-6 and IL-10, the IL-10 concentration was no longer predictive. Therefore, APACHE II scores and either IL-6 or IL-10 concentration may be the most reliable parameters for stratification of patients in future studies of severe gram-negative sepsis.
Assuntos
Citocinas/sangue , Melioidose/imunologia , Melioidose/mortalidade , APACHE , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bacteriemia/microbiologia , Biomarcadores/sangue , Burkholderia pseudomallei/isolamento & purificação , Ceftazidima/uso terapêutico , Cefalosporinas/uso terapêutico , Feminino , Humanos , Imipenem/uso terapêutico , Interleucina-10/sangue , Interleucina-6/sangue , Lactatos/sangue , Modelos Logísticos , Masculino , Melioidose/diagnóstico , Melioidose/tratamento farmacológico , Pessoa de Meia-Idade , Prognóstico , Tienamicinas/uso terapêutico , Fator de Necrose Tumoral alfa/metabolismoRESUMO
A prospective, open, randomized, comparative treatment trial was conducted to compare the therapeutic efficacy of the conventional four-drug combination (chloramphenicol, trimethoprim-sulfamethoxazole, and doxycycline) with that of doxycycline alone in oral maintenance treatment of melioidosis. Adult Thai patients with culture-confirmed melioidosis were randomized to receive treatment with either regimen for a minimum of 12 weeks, usually following intravenous treatment of severe disease. The main outcome measure was culture-confirmed relapse. One hundred sixteen patients were enrolled; 109 had culture-confirmed melioidosis, and 87 were considered evaluable (43 had received doxycycline). Culture-confirmed relapse occurred in one patient randomized to the conventional regimen and in 11 (25.6%) randomized to the doxycycline regimen (P = .009), and treatment failed for 8 (18.2%) versus 20 (46.5%), respectively (P = .009). Adverse effects occurred in 26% of patients overall. Doxycycline alone cannot be recommended for a first-line regimen of oral maintenance treatment of melioidosis.
Assuntos
Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Cloranfenicol/uso terapêutico , Doxiciclina/uso terapêutico , Quimioterapia Combinada/uso terapêutico , Melioidose/tratamento farmacológico , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Adolescente , Adulto , Idoso , Antibacterianos/efeitos adversos , Anti-Infecciosos/efeitos adversos , Cloranfenicol/efeitos adversos , Doxiciclina/efeitos adversos , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Falha de Tratamento , Resultado do Tratamento , Combinação Trimetoprima e Sulfametoxazol/efeitos adversosRESUMO
An open, prospective, randomized, comparative treatment trial was conducted to compare the therapeutic efficacy of high-dose intravenous imipenem and ceftazidime for acute severe melioidosis. Adult Thai patients with suspected acute, severe melioidosis were randomized to receive either imipenem, at a dosage of 50 mg/(kg x d), or ceftazidime, at a dosage of 120 mg/(kg x d), for a minimum of 10 days. The main outcome measures were death or treatment failure. Of the 296 patients enrolled, 214 had culture-confirmed melioidosis, and 132 (61.7%) of them had positive blood cultures. Mortality among patients with melioidosis was 36.9% overall. There were no differences in survival overall (P = .96) or after 48 hours (P = .3). Treatment failure after 48 hours was more common among patients treated with ceftazidime (P = .011). Both treatments were well tolerated. Imipenem is a safe and effective treatment for acute severe melioidosis and may be considered an alternative to ceftazidime.
Assuntos
Ceftazidima/uso terapêutico , Cefalosporinas/uso terapêutico , Imipenem/uso terapêutico , Melioidose/tratamento farmacológico , Tienamicinas/uso terapêutico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Ceftazidima/efeitos adversos , Cefalosporinas/efeitos adversos , Feminino , Humanos , Imipenem/efeitos adversos , Masculino , Melioidose/mortalidade , Melioidose/fisiopatologia , Pessoa de Meia-Idade , Estudos Prospectivos , Tienamicinas/efeitos adversos , Falha de Tratamento , Resultado do TratamentoAssuntos
Antifúngicos/uso terapêutico , Criptococose/tratamento farmacológico , Cryptococcus neoformans/efeitos dos fármacos , Infecções Oportunistas Relacionadas com a AIDS/complicações , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Criptococose/complicações , Humanos , TailândiaRESUMO
Decreased erythropoiesis and increased clearance of both parasitized and noninfected erythrocytes both contribute to the pathogenesis of anemia in falciparum malaria. Erythrocytes with reduced deformability are more likely to be cleared from the circulation by the spleen, a process that is augmented in acute malaria. Using a laser diffraction technique, we measured red blood cell (RBC) deformability over a range of shear stresses and related this to the severity of anemia in 36 adults with severe falciparum malaria. The RBC deformability at a high shear stress of 30 Pa, similar to that encountered in the splenic sinusoids, showed a significant positive correlation with the nadir in hemoglobin concentration during hospitalization (r = 0.49, P < 0.002). Exclusion of five patients with microcytic anemia strengthened this relationship (r = 0.64, P < 0.001). Reduction in RBC deformability resulted mainly from changes in unparasitized erythrocytes. Reduced deformability of uninfected erythrocytes at high shear stresses and subsequent splenic removal of these cells may be an important contributor to the anemia of severe malaria.
Assuntos
Anemia/etiologia , Deformação Eritrocítica , Malária Falciparum/sangue , Malária Falciparum/complicações , Adulto , Anemia/sangue , Hemoglobinas/análise , Humanos , Valor Preditivo dos Testes , Índice de Gravidade de DoençaRESUMO
Penicillium marneffei is a major cause of opportunistic infection in patients with AIDS in north and northeastern Thailand. A method for the quantitation of P. marneffei antigen in urine was developed by using fluorescein isothiocyanate-labelled purified rabbit hyperimmune immunoglobulin G in an enzyme-linked immunosorbent assay. This method was evaluated with 33 patients with culture-proven penicilliosis and 300 controls (52 healthy subjects, 248 hospitalized patients without penicilliosis) from the same area in which penicilliosis is endemic. Urinary antigen was found in all 33 (100%) patients with penicilliosis, with a median titer of 1:20,480. With undiluted samples, 67 (27%) of 248 hospital patients and 3 (6%) of 52 healthy controls were reactive. At a cutoff titer of 1:40, the urine antigen detection assay had a diagnostic sensitivity of 97% and specificity of 98% (positive predictive value, 84%; negative predictive value, 99.7%). This test offers a valuable and rapid method for the diagnosis of penicilliosis in patients with AIDS and could be a useful addition to conventional diagnostic methods in areas in which penicilliosis is endemic.
Assuntos
Antígenos de Fungos/urina , Ensaio de Imunoadsorção Enzimática/métodos , Micoses/diagnóstico , Penicillium/isolamento & purificação , Adulto , Doenças Endêmicas , Estudos de Avaliação como Assunto , Fluoresceína-5-Isotiocianato , Humanos , Imunoensaio , Técnicas Microbiológicas , Micoses/epidemiologia , Micoses/microbiologia , Micoses/urina , Penicillium/imunologia , Estudos Prospectivos , Sensibilidade e Especificidade , Tailândia/epidemiologiaRESUMO
In all experimental mammals tested (rats, dogs, primates), intramuscular injections of the oil-soluble antimalarial artemisinin derivatives artemether and arteether have produced an unusual pattern of selective damage to brain stem centers predominantly involved in auditory processing and vestibular reflexes. Artesunate, the most widely used of these compounds, is a water soluble hemisuccinate derivative given parenterally either by intravenous or intramuscular injection. The neurotoxic potential of parenteral artesunate and artemether was compared in a murine model. Adult Swiss albino mice were assigned randomly to 28-day regimens of intramuscular artemether or artesunate in doses ranging from 30 to 100 mg/kg/day. At 30 mg/kg/day, no abnormalities were detected with either drug. At 50 mg/kg/day, abnormalities were observed in six of 12 artemether recipients and two of 12 artesunate recipients. These were reversible in all but one (artemether) mouse. At 100 mg/kg/day, eight of 36 artemether recipients, two of 36 artesunate recipients, and one of 18 control mice died. All but four surviving mice in the artemether group (86%) showed obvious and usually irreversible abnormalities of balance and equilibrium, whereas only four artesunate recipients (11%) exhibited abnormalities, and these were reversible in each case (P < 0.001). At this dose the relative risk (95% confidence interval) for death or disability was 5.3 (2.6-11.2) for artemether recipients. Intramuscular artemether is significantly more neurotoxic than intramuscular artesunate in this murine model.
Assuntos
Antimaláricos/toxicidade , Artemisininas , Tronco Encefálico/efeitos dos fármacos , Sesquiterpenos/toxicidade , Animais , Artemeter , Artesunato , Comportamento Animal/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Feminino , Injeções Intramusculares , CamundongosRESUMO
It has been suggested that nitric oxide (NO) plays an important role in the pathogenesis of severe falciparum malaria. Since NO has a very short half-life, nitrate and nitrite (NOx) levels, stable metabolites of NO, are used as measures of NO production. We measured plasma NOx levels in 24 adults with severe falciparum malaria on the Thai-Burmese border. After correction for renal function, there was no correlation between plasma NOx levels, or the total amount of NOx excreted in the urine, and disease severity. Plasma NOx levels decreased after the first 48 hr in all patients (P = 0.007), suggesting decreased NO production. The NOx levels in cerebrospinal fluid (CSF) correlated well with plasma NOx levels, but these did not show a correlation with coma depth, and were not significantly different from those in a healthy control group. These findings do not support the hypothesis that excessive NO production contributes to the pathogenesis of severe falciparum malaria. However, local changes in NO production, e.g., in the central nervous system, might not be reflected in the total NOx production or NOx levels in the CSF.
Assuntos
Malária Falciparum/metabolismo , Óxido Nítrico/análise , Adulto , Creatinina/sangue , Creatinina/urina , Humanos , Nitratos/sangue , Nitratos/urina , Óxido Nítrico/sangue , Óxido Nítrico/líquido cefalorraquidiano , Óxido Nítrico/urina , Nitritos/sangue , Nitritos/urina , Índice de Gravidade de DoençaRESUMO
Severe falciparum malaria is associated with microvascular obstruction resulting from sequestration of erythrocytes containing mature stages of the parasite. Since reduced red blood cell deformability (RBC-D) can contribute to impaired microcirculatory flow, RBC-D was measured in 23 patients with severe falciparum malaria (seven of whom subsequently died), 30 patients with uncomplicated malaria, and 17 healthy controls. The RBC-D, measured by ektacytometry, was significantly reduced in severe malaria and was particularly low in all fatal cases. At a low shear stress of 1.7 Pascal (Pa), a red blood cell elongation index less than 0.21 on admission to the hospital predicted fatal outcome with a sensitivity of 100% (confidence interval [CI] = 59-100%) and a specificity of 88% (CI = 61-98%). The reduction in the RBC-D appeared to result mainly from changes in unparasitized erythrocytes. Reduced deformability of unparasitized red blood cells in severe malaria may contribute to impaired microcirculatory flow and a fatal outcome in severe falciparum malaria.
Assuntos
Deformação Eritrocítica , Malária Falciparum/sangue , Adulto , Humanos , Microcirculação , PrognósticoRESUMO
Two distinct types of Burkholderia pseudomallei, differentiated by the ability to assimilate L-arabinose but with similar morphologies and antigenicities, can be isolated from soil in Thailand. Approximately 25% of soil isolates from northeast Thailand were arabinose assimilators (Ara+), but in 1,200 sequentially studied patients, only arabinose "nonassimilators" (Ara-) caused melioidosis (P < 0.0001). In a murine model, there was a striking difference in virulence between Ara- and Ara+ B. pseudomallei. The mean (standard deviation) 50% lethal dose (LD[50]) inoculum for Ara- isolates was 182 (111) CFU/mouse compared with approximately 10(9) CFU/mouse for Ara+ soil isolates. There was no significant difference between the LD(50)s for clinical and soil Ara- isolates. All attempts to convert the biochemical phenotype by selective culture failed, which suggests that the biotype is stable.
Assuntos
Arabinose/metabolismo , Burkholderia pseudomallei/classificação , Burkholderia pseudomallei/patogenicidade , Melioidose/microbiologia , Microbiologia do Solo , Animais , Técnicas de Tipagem Bacteriana , Burkholderia pseudomallei/metabolismo , Humanos , Dose Letal Mediana , Melioidose/mortalidade , Camundongos , Camundongos Endogâmicos BALB C , Fenótipo , Estudos Prospectivos , TailândiaRESUMO
During acute falciparum malaria infection, red blood cells (RBC) containing abundant ring-infected erythrocyte surface antigen (Pf 155 or RESA), but no intracellular parasites, are present in the circulation. These RESA-positive parasite negative RBC are not seen in parasite cultures in vitro. This indicates that in acute falciparum malaria there is active removal of intraerythrocytic parasites by a host mechanism in vivo (probably the spleen) without destruction of the parasitized RBC. This may explain the observed disparity between the drop in hematocrit and decrease in parasite count in some hyperparasitemic patients. The fate of these "once-parasitized" RBC in vivo is not known.