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1.
HIV Med ; 19(3): 175-183, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29159965

RESUMO

OBJECTIVES: Dyslipidaemia is common in perinatally HIV-infected (PHIV) youth receiving protease inhibitors (PIs). Few studies have evaluated longitudinal lipid changes in PHIV youth after switch to newer PIs. METHODS: We compared longitudinal changes in fasting lipids [total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and TC:HDL-C ratio] in PHIV youth enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS) Adolescent Master Protocol (AMP) study who switched to atazanavir/ritonavir (ATV/r)- or darunavir/ritonavir (DRV/r)-based antiretroviral therapy (ART) from an older PI-based ART and those remaining on an older PI. Generalized estimating equation models were fitted to assess the association of a switch to ATV/r- or DRV/r-based ART with the rate of change in lipids, adjusted for potential confounders. RESULTS: From 2007 to 2014, 47 PHIV children/adolescents switched to ATV/r or DRV/r, while 120 remained on an older PI [primarily lopinavir/r (72%) and nelfinavir (24%)]. Baseline age ranged from 7 to 21 years. After adjustment for age, Tanner stage, race/ethnicity, and HIV RNA level, a switch to ATV/r or DRV/r was associated with a more rapid annual rate of decline in the ratio of TC:HDL-C. (ß = -0.12; P = 0.039) than remaining on an older PI. On average, TC declined by 4.57 mg/dL/year (P = 0.057) more in the switch group. A switch to ATV/r or DRV/r was not associated with the rate of HDL-C, LDL-C, or TG change. CONCLUSIONS: A switch to ATV/r or DRV/r may result in more rapid reduction in TC and the TC:HDL-C ratio in PHIV youth, potentially impacting long-term cardiovascular disease risk.


Assuntos
Sulfato de Atazanavir/uso terapêutico , Darunavir/uso terapêutico , Dislipidemias/metabolismo , Infecções por HIV/tratamento farmacológico , Inibidores da Protease de HIV/uso terapêutico , Lipídeos/análise , Ritonavir/uso terapêutico , Adolescente , Criança , Estudos de Coortes , Quimioterapia Combinada , Dislipidemias/induzido quimicamente , Feminino , HIV-1/efeitos dos fármacos , Humanos , Estudos Longitudinais , Masculino , Carga Viral/efeitos dos fármacos , Adulto Jovem
2.
HIV Med ; 13(5): 264-75, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22136114

RESUMO

OBJECTIVES: HIV-infected children may be at risk for premature cardiovascular disease. We compared levels of biomarkers of vascular dysfunction in HIV-infected children (with and without hyperlipidaemia) with those in HIV-exposed, uninfected (HEU) children enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS), and determined factors associated with these biomarkers. METHODS: A prospective cohort study was carried out. Biomarkers of inflammation [C-reactive protein (CRP), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP1)], coagulant dysfunction (fibrinogen and P-selectin), endothelial dysfunction [soluble intracellular cell adhesion molecule-1 (sICAM), soluble vascular cell adhesion molecule-1 (sVCAM) and E-selectin], and metabolic dysfunction (adiponectin) were measured in 226 HIV-infected and 140 HEU children. Anthropometry, body composition, lipids, glucose, insulin, HIV disease severity, and antiretroviral therapy were recorded. RESULTS: The median ages of the children were 12.3 years in the HIV-infected group and 10.1 years in the HEU group. Body mass index (BMI) z-scores, waist and hip circumferences, and percentage body fat were lower in the HIV-infected children. Total and non-high-density lipoprotein (HDL) cholesterol and triglycerides were higher in HIV-infected children. HIV-infected children also had higher MCP-1, fibrinogen, sICAM and sVCAM levels. In multivariable analyses in the HIV-infected children alone, BMI z-score was associated with higher CRP and fibrinogen, but lower MCP-1 and sVCAM. Unfavourable lipid profiles were positively associated with IL-6, MCP-1, fibrinogen, and P- and E-selectin, whereas increased HIV viral load was associated with markers of inflammation (MCP-1 and CRP) and endothelial dysfunction (sICAM and sVCAM). CONCLUSIONS: HIV-infected children have higher levels of biomarkers of vascular dysfunction than do HEU children. Risk factors associated with higher biomarkers include unfavourable lipid levels and active HIV replication.


Assuntos
Doenças Cardiovasculares/sangue , Infecções por HIV/sangue , HIV-1/fisiologia , Replicação Viral/fisiologia , Adolescente , Biomarcadores/sangue , Proteína C-Reativa/análise , Moléculas de Adesão Celular/sangue , Quimiocina CCL2/sangue , Criança , Estudos de Coortes , Selectina E/sangue , Feminino , Fibrinogênio/análise , Infecções por HIV/fisiopatologia , Humanos , Hiperlipidemias/sangue , Interleucina-6/sangue , Masculino , Análise Multivariada , Selectina-P/sangue , Fatores de Risco
3.
J Clin Invest ; 76(2): 676-84, 1985 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2411761

RESUMO

In these studies, we have used several approaches to systematically explore the contribution of transcellular vesicular transport (transcytosis) to the blood-to-bile movement of inert fluid-phase markers of widely varying molecular weight. First, under steady-state conditions, the perfused rat liver secreted even large markers in appreciable amounts. The bile-to-plasma (B/P) ratio of these different markers, including microperoxidase (B/P ratio = 0.06; mol wt = 1,879), insulin (B/P ratio = 0.09, mol wt = 5,000), horseradish peroxidase (B/P ratio = 0.04, mol wt = 40,000), and dextran (B/P ratio = 0.09, mol wt = 70,000), exhibited no clear ordering based on size alone, and when dextrans of two different sizes (40,000 and 70,000 mol wt) were studied simultaneously, the relative amounts of the two dextran species in bile were the same as in perfusate. Taurocholate administration produced a 71% increase in bile flow but little or no (0-20%) increase in the output of horseradish peroxidase, microperoxidase, inulin, and dextran. Second, under nonsteady-state conditions in which the appearance in or disappearance from bile of selected markers was studied after their abrupt addition to or removal from perfusate, erythritol reached a B/P ratio of 1 within 2 min. Microperoxidase and dextran appeared in bile only after a lag period of approximately 12 min and then slowly approached maximal values, whereas sucrose exhibited kinetically intermediate behavior. A similar pattern was observed after removal of greater than 95% of the marker from the perfusate. Erythritol rapidly reapproached a B/P ratio of 1, whereas the B/P ratio for sucrose, dextran, and microperoxidase fell much more slowly and exceeded 1 for a full 30 min after perfusate washout. Finally, electron microscopy and fluorescence microscopy of cultured hepatocytes demonstrated the presence of horseradish peroxidase and fluorescein-dextran, respectively, in intracellular vesicles, and fractionation of perfused liver homogenates revealed that at least 35-50% of sucrose, inulin, and dextran was associated with subcellular organelles. Collectively, these observations are most compatible with a transcytosis pathway that contributes minimally to the secretion of erythritol, but accounts for a substantial fraction of sucrose secretion and virtually all (greater than 95%) of the blood-to-bile transport of microperoxidase and larger markers. These findings have important implications with respect to current concepts of canalicular bile formation as well as with respect to the conventional use of solutes such as sucrose as markers of canalicular or paracellular pathway permeability.


Assuntos
Bile/metabolismo , Fluoresceína-5-Isotiocianato/análogos & derivados , Fígado/metabolismo , Animais , Transporte Biológico , Dextranos , Eritritol/metabolismo , Fluoresceínas , Fígado/ultraestrutura , Microscopia Eletrônica , Peso Molecular , Perfusão , Peroxidases/metabolismo , Ratos
4.
J Clin Invest ; 70(3): 505-17, 1982 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-6286725

RESUMO

To characterize the transport mechanisms responsible for formation of canalicular bile, we have examined the effects of ion substitution on bile acid-dependent and bile acid-independent bile formation by the isolated perfused rat liver. Complete replacement of perfusate sodium with choline and lithium abolished taurocholate-induced choleresis and reduced biliary taurocholate output by greater than 70%. Partial replacement of perfusate sodium (25 of 128 mM) by choline reduced bile acid-independent bile formation by 30% and replacement of the remaining sodium (103 mM) by choline reduced bile acid-independent bile formation by an additional 64%. In contrast, replacement of the remaining sodium (103 mM) by lithium reduced bile acid-independent bile formation by only an additional 20%, while complete replacement of sodium (128 mM) by lithium reduced bile formation by only 17%, and lithium replaced sodium as the predominant biliary cation. Replacement of perfusate bicarbonate by Tricine, a zwitterionic amino acid buffer, decreased bile acid-independent bile formation by greater than or equal to 50% and decreased biliary bicarbonate output by approximately 60%, regardless of the accompanying cation. In separate experiments, replacement of sodium by lithium essentially abolished Na,K-ATPase activity measured either as ouabain-suppressible ATP hydrolysis in rat liver or kidney homogenates, or as ouabain-suppressible 86Rb uptake by cultured rat hepatocytes. These studies indicate that bile acid(taurocholate)-dependent bile formation by rat liver exhibits a specific requirement for sodium, a finding probably attributable to the role(s) of sodium in hepatic sodium-coupled taurocholate uptake and/or in maintenance of Na,K-ATPase activity. The surprising finding that bile acid-independent bile formation was substantially unaltered by complete replacement of sodium with the permeant cation lithium does not appear to be explained by Na,K-ATPase-mediated lithium transport. Although alternative interpretations exist, this observation is consistent with the hypothesis that much of basal bile acid-independent bile formation is attributable to an ion pump other than Na,K-ATPase, which directly or indirectly mediates bicarbonate transport.


Assuntos
Ácidos e Sais Biliares/metabolismo , Bile/metabolismo , Fígado/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Ânions/farmacologia , Bicarbonatos/farmacologia , Transporte Biológico Ativo , Cátions Monovalentes/farmacologia , Rim/enzimologia , Fígado/enzimologia , Masculino , Ratos , Taxa Secretória/efeitos dos fármacos , Sódio/fisiologia
5.
Biochim Biophys Acta ; 812(2): 423-36, 1985 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-2857093

RESUMO

We have systematically investigated certain characteristics of the ATP-dependent proton transport mechanism of bovine brain clathrin-coated vesicles. H+ transport specific activity was shown by column chromatograpy to co-purify with coated vesicles, however, the clathrin coat is not required for vesicle acidification as H+ transport was not altered by prior removal of the clathrin coat. Acidification of the vesicle interior, measured by fluorescence quenching of acridine orange, displayed considerable anion selectively (Cl- greater than Br- much greater than NO3- much greater than gluconate, SO2-(4), HPO2-(4), mannitol; Km for Cl- congruent to 15 mM), but was relatively insensitive to cation replacement as long as Cl- was present. Acidification was unaffected by ouabain or vanadate but was inhibited by N-ethylmaleimide (IC50 less than 10 microM), dicyclohexylcarbodiimide (DCCD) (IC50 congruent to 10 microM), chlorpromazine (IC50 congruent to 15 microM), and oligomycin (IC50 congruent to 3 microM). In contrast to N-ethylmaleimide, chlorpromazine rapidly dissipated preformed pH gradients. Valinomycin stimulated H+ transport in the presence of potassium salts (gluconate much greater than NO3- greater than Cl-), and the membrane-potential-sensitive dye Oxonol V demonstrated an ATP-dependent interior-positive vesicle membrane potential which was greater in the absence of permeant anions (mannitol greater than potassium gluconate greater than KCl) and was abolished by N-ethylmaleimide, protonophores or detergent. Total vesicle-associated ouabain-insensitive ATPase activity was inhibited 64% by 1 mM N-ethylmaleimide, and correlated poorly with H+ transport, however N-ethylmaleimide-sensitive ATPase activity correlated well with proton transport (r = 0.95) in the presence of various Cl- salts and KNO3. Finally, vesicles prepared from bovine brain synaptic membranes exhibited H+ transport activity similar to that of the coated vesicles.(ABSTRACT TRUNCATED AT 400 WORDS)


Assuntos
Encéfalo/ultraestrutura , Clatrina/metabolismo , Invaginações Revestidas da Membrana Celular/enzimologia , Endossomos/enzimologia , ATPases Translocadoras de Prótons/metabolismo , Laranja de Acridina/metabolismo , Animais , Encéfalo/enzimologia , Carbonil Cianeto m-Clorofenil Hidrazona/farmacologia , Bovinos , Cloretos/farmacologia , Clorpromazina/farmacologia , Dicicloexilcarbodi-Imida/farmacologia , Concentração de Íons de Hidrogênio , Potenciais da Membrana/efeitos dos fármacos , Microscopia Eletrônica , Peso Molecular , Ouabaína/farmacologia , Valinomicina/farmacologia
6.
Subcell Biochem ; 27: 331-60, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8993165

RESUMO

Lysosomes, endosomes, and a variety of other intracellular organelles are acidified by a family of unique proton pumps, termed the vacuolar H(+)-ATPases, that are evolutionarily related to bacterial membrane proton pumps and the F1-F0 H(+)-ATPases that catalyze ATP synthesis in mitochondria and chloroplasts. The electrogenic vacuolar H(+)-ATPase is responsible for generating electrical and chemical gradients across organelle membranes with the magnitude of these gradients ultimately determined by both proton pump regulatory mechanisms and, more importantly, associated ion and organic solute transporters located in vesicle membranes. Analogous to Na+, K(+)-ATPase on the cell membrane, the vacuolar proton pump not only acidifies the vesicle interior but provides a potential energy source for driving a variety of coupled transporters, many of them unique to specific organelles. Although the basic mechanism for organelle acidification is now well understood, it is already apparent that there are many differences in both the function of the proton pump and the associated transporters in different organelles and different cell types. These differences and their physiologic and pathophysiologic implications are exciting areas for future investigation.


Assuntos
Endossomos/metabolismo , Lisossomos/metabolismo , Animais , Humanos , Concentração de Íons de Hidrogênio , Transporte de Íons
7.
AIDS ; 12(14): 1805-13, 1998 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-9792381

RESUMO

OBJECTIVE: To determine the safety of the zidovudine (ZDV) regimen utilized in the Pediatric AIDS Clinical Trial Group (ACTG) 076 study. DESIGN: ACTG 076 was a randomized, double-blind, placebo-controlled trial which demonstrated that a ZDV regimen could prevent mother-to-child HIV-1 transmission. Infants were followed through 18 months of age and women were followed through 6 months postpartum. METHODS: Maternal complications, pregnancy outcomes, growth and development of the uninfected infants, and HIV-1 disease progression in the women were monitored prospectively. RESULTS: Maternal therapy was well tolerated. There was no serious pattern of adverse pregnancy outcomes associated with ZDV use. Amongst the ZDV-exposed infants, the only recognized toxicity was anemia within the first 6 weeks of life; the risk for anemia was not associated with premature delivery, duration of maternal treatment, degree of maternal immunosuppression, or maternal anemia. ZDV treatment was not associated with an increased incidence of newborn structural abnormalities. At 18 months of age, uninfected infants did not differ in growth parameters or immune function. No childhood neoplasias were reported in either group. In the women, at 6 months postpartum, there were no differences in clinical, immunologic, or virologic disease progression. CONCLUSION: There were no identified problems that would alter current recommendations for the routine use of ZDV for the prevention of mother-child HIV-1 transmission.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Infecções por HIV/transmissão , HIV-1 , Transmissão Vertical de Doenças Infecciosas , Complicações Infecciosas na Gravidez/tratamento farmacológico , Zidovudina/uso terapêutico , Fármacos Anti-HIV/efeitos adversos , Progressão da Doença , Método Duplo-Cego , Feminino , França , Humanos , Lactente , Recém-Nascido , Gravidez , Complicações na Gravidez/induzido quimicamente , Resultado da Gravidez , Estados Unidos , Zidovudina/efeitos adversos
8.
AIDS ; 14(10): 1389-99, 2000 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-10930154

RESUMO

OBJECTIVE: To evaluate independent contributions of maternal factors to adverse pregnancy outcomes (APO) in HIV-infected women receiving antiretroviral therapy (ART). DESIGN: Risk factors for preterm birth (< 37 weeks gestation), low birth weight (LBW) (< 2500 g), and intrauterine growth retardation (IUGR) (birth weight < 10th percentile for gestational age) examined in 497 HIV-infected pregnant women enrolled in PACTG 185, a perinatal clinical trial. METHODS: HIV RNA copy number, culture titer, and CD4 lymphocyte counts were measured during pregnancy. Information collected included antenatal use of cigarettes, alcohol, illicit drugs; ART; obstetric history and complications. RESULTS: Eighty-six percent were minority race/ethnicity; 86% received antenatal monotherapy, predominantly zidovudine (ZDV), and 14% received combination antiretrovirals. Preterm birth occurred in 17%, LBW in 13%, IUGR in 6%. Risk of preterm birth was independently associated with prior preterm birth [odds ratio (OR) 3.34; P < 0.001], multiple gestation (OR, 6.02; P = 0.011), antenatal alcohol use (OR, 1.91; P = 0.038), and antenatal diagnosis of genital herpes (OR, 0.24; P = 0.022) or pre-eclampsia (OR, 6.36; P = 0.025). LBW was associated with antenatal diagnosis of genital herpes (OR, 0.08; P = 0.014) and pre-eclampsia (OR, 5.25; P = 0.049), and baseline HIV culture titer (OR, 1.41; P = 0.037). IUGR was associated with multiple gestation (OR, 8.20; P = 0.010), antenatal cigarette use (OR, 3.60; P = 0.008), and pre-eclampsia (OR, 12.90; P = 0.007). Maternal immune status and HIV RNA copy number were not associated with APO. CONCLUSIONS: Risk factors for APO in antiretroviral treated HIV-infected women are similar to those reported for uninfected women. These data suggest that provision of prenatal care and ART may reduce APO.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Retardo do Crescimento Fetal/etiologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Complicações Infecciosas na Gravidez/tratamento farmacológico , Zidovudina/uso terapêutico , Adulto , Método Duplo-Cego , Feminino , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Recém-Nascido Prematuro , Análise Multivariada , Gravidez , Fatores de Risco
9.
Cell Calcium ; 11(8): 515-24, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2265428

RESUMO

The affects of volatile anesthetics on mobilization of intracellular Ca2+ was monitored in primary cultures of rat hepatocytes using the fluorescent Ca2+ probe Fura-2. The use of Fura-2 was limited by several factors which complicated the quantitative analysis of the results, such as: (i) a high rate of dye leakage; (ii) changes in the redox state of the hepatocytes which interfered with the fluorescence produced by the dye at various excitation wavelengths; (iii) compartmentalization of the dye producing high local intracellular concentrations; and, of particular importance for this study, (iv) enhanced photobleaching of the dye in the presence of halothane. To aid in the interpretation of the Fura-2 data, the Ca2(+)-sensitive photoprotein aequorin was also used to monitor changes in [Ca2+]i. The aequorin and Fura-2 techniques qualitatively yielded the same result, that the volatile anesthetic agents halothane, enflurane, and isoflurane induce an immediate and transient increase of [Ca2+]i. The durations of these transients were approximately between 5 and 10 min and were not related to any evident acute cell toxicity. The [Ca2+]i increases induced by the volatile anesthetic agents were dose-dependent, with halothane the most potent. The exact mechanism governing these increases in [Ca2+]i induced by these anesthetics in rat hepatocytes is unknown, but is likely to involve effects on both the cell surface membrane and endoplasmic reticulum components of the signal transducing system.


Assuntos
Anestésicos/farmacologia , Cálcio/metabolismo , Fígado/efeitos dos fármacos , Equorina/metabolismo , Animais , Compartimento Celular , Células Cultivadas , Enflurano/farmacologia , Fura-2/metabolismo , Fura-2/efeitos da radiação , Halotano/farmacologia , Ionomicina/farmacologia , Isoflurano/farmacologia , Fígado/metabolismo , Masculino , Fotoquímica , Ratos , Ratos Endogâmicos , Vasopressinas/farmacologia
10.
FEBS Lett ; 237(1-2): 15-20, 1988 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-3169235

RESUMO

Resonance Raman (RR) and absorption spectroscopic studies of purified rabbit liver cytochromes P-450 show that the form 2 isomer (LM2) but not the form 4 isomer (LM4) forms a long-lived complex with halothane after dithionite reduction, absorbing light at 470 nm, in which ferric 6-coordinated heme iron in the low-spin configuration is liganded to 2-chloro-1,1-difluoroethylene. The RR data exclude the possibility that the CF3CHCl- carbanion is a ligand and are consistent with the involvement of an active-site pocket in the cytochrome P-450 polypeptide.


Assuntos
Sistema Enzimático do Citocromo P-450/metabolismo , Halotano/metabolismo , Isoenzimas/metabolismo , Microssomos Hepáticos/metabolismo , Animais , Ligação Proteica , Coelhos , Espectrofotometria , Análise Espectral Raman/métodos
11.
Am J Med ; 73(1A): 172-5, 1982 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-7102701

RESUMO

The pharmacokinetics of acyclovir administrated orally in a dose of 200 mg every four hours, five times a day to adults with herpes progenitalis was determined. Peak plasma acyclovir levels are found 1.5 to 1.75 hours after oral administration; peak levels range from 1.4 to 4.0 microM with a mean of 2.5 microM. Acyclovir levels in saliva are well correlated with simultaneous plasma levels, saliva levels being approximately 13 percent of plasma levels. Simultaneous plasma and vaginal secretion acyclovir levels are poorly correlated; peak levels in vaginal secretions range from 0.5 to 3.6 microM.


Assuntos
Antivirais/metabolismo , Guanina/análogos & derivados , Herpes Genital/tratamento farmacológico , Aciclovir , Administração Oral , Adulto , Feminino , Guanina/metabolismo , Humanos , Cinética , Masculino , Recidiva , Saliva/análise , Distribuição Tecidual , Vagina/metabolismo
12.
Biochem Pharmacol ; 33(2): 255-60, 1984 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-6704150

RESUMO

Dichlorodi[U-14C]phenyltrichloroethane ( [14C]DDT), incubated with rat hepatic microsomes and NADPH, produced reactive intermediates which covalently bound to microsomal protein and lipids. In atmospheric oxygen, DDT bound to microsomal protein; however, binding was increased up to approximately 70% by oxygen depletion. Low levels of [14C]DDT binding to microsomal lipids occurred under atmospheric oxygen but, in contrast to protein binding, DDT-phospholipid binding was increased up to 20-fold by oxygen depletion. Dichlorodiphenyldichloroethane (DDD) was rapidly formed from DDT under anaerobic conditions, although when DDD was utilized as substrate, binding to microsomal protein occurred only in the presence of oxygen. Sodium dithionite, added to microsomes, produced [14C]DDT phospholipid and protein binding, and DDD formation, but failed to support DDD metabolism or binding. The data are consistent with the reductive formation of a DDT free-radical intermediate that led to the formation of DDD and that was bound preferentially to microsomal lipids.


Assuntos
DDT/metabolismo , Diclorodifenildicloroetano/metabolismo , Metabolismo dos Lipídeos , Microssomos Hepáticos/metabolismo , Proteínas/metabolismo , Animais , Masculino , Ligação Proteica , Ratos , Ratos Endogâmicos
13.
Biochem Pharmacol ; 37(12): 2357-61, 1988 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-3390202

RESUMO

The reductive metabolism of halothane was determined using purified RLM2, PBRLM4 and PBRLM5 forms of rat liver microsomal cytochrome P-450. The metabolites, 2-chloro-1,1,1-trifluoroethane (CTE) and 2-chloro-1,1-difluoroethylene (CDE), were determined. All three forms of cytochrome P-450 produced CTE with relatively small differences in its production among the various forms. There were major differences, however, in the production of CDE, with PBRLM5 being the most active. PBRLM5 was also the only form to show the development of a complex between halothane and cytochrome P-450. This complex absorbed light maximally at 470 nm. The complex formation and the production of CDE by PBRLM5 were stimulated by the addition of cytochrome b5. Cytochrome b5 had no effect on CDE production by PBRLM4 and inhibited the production of both CTE and CDE by RLM2. These results show that the two-electron reduction of halothane by cytochrome P-450 was catalyzed by the PBRLM5 form and that cytochrome b5 stimulated the transfer of the second electron to halothane through PBRLM5, but not RLM2 or PBRLM4.


Assuntos
Sistema Enzimático do Citocromo P-450/farmacologia , Halotano/metabolismo , Animais , Grupo dos Citocromos b/farmacologia , Citocromos b5 , Masculino , Oxirredução , Ratos
14.
Biochem Pharmacol ; 36(7): 1029-34, 1987 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-3566799

RESUMO

Under anaerobic conditions, various halogenated compounds, when metabolized by cytochrome P-450, form complexes which are spectrally detectable. Previous studies have shown that halothane forms such a complex with cytochrome P-450, and the result is a strong absorption at 470 nm. Stabilization of this proposed intermediate carbanion complex has never been demonstrated in a biological system. Data are presented which show that several organic solvents (C5-C7N-alkanes) will stabilize the complex formed between halothane and cytochrome P-450. Stabilization allowed the decay of the complex to be studied, and it is demonstrated that the product of decay was chlorodifluoroethylene, which substantiates the hypothesis that the complex is a two electron-reduced carbanion. Carbon tetrachloride and benzyl bromide, which also produce spectrally visible intermediate complexes, were not stabilized by this treatment. Stabilization of the halothane complex in a biological system may facilitate studies to identify precisely the halothane-cytochrome P-450 complex and to clarify the mechanisms of halothane reduction by cytochrome P-450.


Assuntos
Alcanos/farmacologia , Anilina Hidroxilase/metabolismo , Hidrocarboneto de Aril Hidroxilases/metabolismo , Compostos de Benzil/metabolismo , Tetracloreto de Carbono/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Microssomos Hepáticos/metabolismo , Oxirredutases N-Desmetilantes/metabolismo , Animais , Cinética , Masculino , Ligação Proteica , Ratos , Ratos Endogâmicos , Relação Estrutura-Atividade
15.
Biochem Pharmacol ; 36(7): 1023-7, 1987 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-3566798

RESUMO

The effects of the volatile anesthetics, enflurane, isoflurane and halothane, on the pharmacokinetics of antipyrine were examined in mice. The administration of 0.75% isoflurane or 1.0% enflurane in air resulted in a 173 and a 206% increase, respectively, in antipyrine plasma half-life and a 29.1 and a 41.2% decrease in antipyrine total body clearance. There was also an almost 2-fold increase in the volume of distribution of antipyrine. Halothane, at 0.5% in air, had no significant effect upon antipyrine plasma half-life or its volume of distribution. There was no significant change in antipyrine total body clearance and volume of distribution 4 hr after exposure to the volatile agents, but there was a small increase in half-life. The exposures to the volatile anesthetics were also carried out in an atmosphere of 8% oxygen. Antipyrine plasma half-life was increased significantly by 48% in mice breathing 8% oxygen, compared to mice breathing air. Isoflurane in 8% oxygen increased the plasma half-life of antipyrine by 296% compared to mice breathing 8% oxygen. This increase was greater than the effect of isoflurane seen in mice breathing air. Mice breathing halothane in 8% oxygen exhibited a 21% increase in antipyrine plasma half-life and mice breathing enflurane in 8% oxygen, a 117% increase in antipyrine plasma half-life, although the changes were not markedly different from those seen in mice breathing air. Enflurane and isoflurane produced a significant increase in the volume of distribution for antipyrine in the mice breathing 8% oxygen. Total body clearance of antipyrine was decreased markedly in mice breathing isoflurane and enflurane but showed a lesser decrease in mice breathing halothane in 8% oxygen. In vitro in mouse microsomes, halothane, enflurane and isoflurane were all inhibitors of aminopyrine metabolism. Possible mechanisms for these results are discussed.


Assuntos
Antipirina/metabolismo , Enflurano/farmacologia , Halotano/farmacologia , Isoflurano/farmacologia , Animais , Cinética , Masculino , Taxa de Depuração Metabólica , Camundongos
16.
Environ Health Perspect ; 21: 121-4, 1977 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-612436

RESUMO

The dechlorination of chlorinated hydrocarbons has been examined in detail. The reaction is catalyzed by cytochrome P-450 and occurs optimally in the presence of oxygen although some dechlorination may occur under anaerobic conditions. Halothane has been shown to undergo an oxidative dechlorination and a reductive defluorination. Enzymatic attack of chlorinated olefins and hydrocarbons is not on the carbon--halogen bond. Oxidative dechlorination of hydrocarbons is apparently initiated by an attack on the carbon atom and the halogen is then released from the oxidized carbon. The chlorinated olefins, on the other hand, are not easily dechlorinated enzymatically. The chlorines migrate readily across the double bond, therefore, cyclic chloronium ions must occur as intermediates. It is not clear at this time if epoxides are also intermediates in this conversion.


Assuntos
Hidrocarbonetos Clorados/metabolismo , Alcenos/metabolismo , Anestésicos/metabolismo , Animais , Biotransformação , Catálise , Sistema Enzimático do Citocromo P-450 , Halotano/metabolismo , Microssomos Hepáticos/metabolismo , Ratos
17.
Mayo Clin Proc ; 64(3): 356-9, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2649750

RESUMO

In a prospective study of 10 patients who underwent liver transplantation and 10 patients who underwent cholecystectomy, we analyzed the postoperative analgesic requirements and the resultant plasma morphine concentrations. Analgesia was more intense, with less medication, and the plasma morphine concentration was significantly lower in the liver transplant group than in the cholecystectomy group. This finding is most likely attributable to endogenous factors rather than to altered morphine pharmacokinetics.


Assuntos
Colecistectomia , Transplante de Fígado , Morfina/administração & dosagem , Dor Pós-Operatória/tratamento farmacológico , Adulto , Peso Corporal , Feminino , Fentanila/administração & dosagem , Fentanila/sangue , Humanos , Rim/fisiologia , Masculino , Pessoa de Meia-Idade , Morfina/sangue , Morfina/farmacocinética , Dor Pós-Operatória/metabolismo , Estudos Prospectivos
18.
Mayo Clin Proc ; 64(2): 224-31, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2646480

RESUMO

Anesthesia support for patients undergoing orthotopic liver transplantation can be complicated because of multiple medical problems in such patients and rapid hemodynamic, metabolic, and coagulation changes intraoperatively. Preoperative assessment should include careful review of the cardiovascular, respiratory, and hematologic systems. Use of isoflurane as the main anesthetic agent will minimize toxicity to the liver. During liver transplantation, hemodynamic monitoring and immediate laboratory studies should be available. In our experience during the first 100 liver transplantations performed at our institution, use of a rapid infusion pump and venovenous bypass has helped normalize hemodynamic and renal function.


Assuntos
Anestesia Geral , Transplante de Fígado , Dopamina/administração & dosagem , Hemodinâmica , Humanos , Bombas de Infusão , Isoflurano/administração & dosagem , Monitorização Fisiológica
19.
Mayo Clin Proc ; 64(2): 232-40, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2646481

RESUMO

In this study, we retrospectively analyzed the intraoperative hemodynamic, laboratory, and coagulation data on the first 83 patients who underwent an initial liver transplantation procedure at our institution. The major hemodynamic changes at the time of reperfusion of the donor liver were significant decreases in arterial blood pressure, systemic vascular resistance, and pulmonary artery temperature and significant increases in cardiac output and pulmonary capillary wedge pressure. The alterations in laboratory values reflected intraoperative therapeutic manipulations. Citrate toxicity is a concern, and the amount of calcium chloride administered reflected the volume of blood transfused. On reperfusion, the fibrinogen concentration decreased and both the prothrombin time and the activated partial thromboplastin time increased. This coagulopathy was also evident in the thromboelastographic values. Aggressive monitoring and prompt intervention are necessary to maintain hemodynamic and metabolic homeostasis in these patients.


Assuntos
Análise Química do Sangue , Hemodinâmica , Transplante de Fígado , Coagulação Sanguínea , Cálcio/sangue , Homeostase , Humanos , Concentração de Íons de Hidrogênio , Período Intraoperatório , Monitorização Fisiológica , Potássio/sangue , Estudos Retrospectivos , Tromboelastografia
20.
Pediatr Infect Dis J ; 15(3): 247-54, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8852914

RESUMO

BACKGROUND: Neonatal herpes simplex virus (HSV) infections limited to the skin, eyes and mouth (SEM) can result in neurologic impairment. A direct correlation exists between the development of neurologic deficits and the frequency of cutaneous HSV recurrences. Thus, the National Institutes of Allergy and Infectious Diseases Collaborative Antiviral Study Group conducted a Phase I/II trial of oral acyclovir therapy for the suppression of cutaneous recurrences after SEM disease in 26 neonates. METHODS: Infants < or = 1 month of age with virologically confirmed HSV-2 SEM disease were eligible for enrollment. Suppressive oral acyclovir therapy (300 mg/m2/dose given either twice daily or three times per day) was administered for 6 months. RESULTS: Twelve (46%) of the 26 infants developed neutropenia (< 1000 cells/mm3) while receiving acyclovir. Thirteen (81%) of the 16 infants who received drug 3 times per day experienced no recurrences of skin lesions while receiving therapy. In comparison, a previous Collaborative Antiviral Study Group study found that only 54% of infants have no cutaneous recurrences in the 6 months after resolution of neonatal HSV disease if oral acyclovir suppressive therapy is not initiated. In one infant, HSV DNA was detected in the cerebrospinal fluid during a cutaneous recurrence, and an acyclovir-resistant HSV mutant was isolated from another patient during the course of the study. CONCLUSIONS: Administration of oral acyclovir can prevent cutaneous recurrences of HSV after neonatal SEM disease. The effect of such therapy on neurologic outcome must be assessed in a larger, Phase III study. As such, additional investigation is necessary before routine use of suppressive therapy in this population can be recommended.


Assuntos
Aciclovir/uso terapêutico , Antivirais/uso terapêutico , Infecções Oculares Virais/tratamento farmacológico , Herpes Genital/tratamento farmacológico , Herpesvirus Humano 2/efeitos dos fármacos , Doenças da Boca/tratamento farmacológico , Dermatopatias Virais/tratamento farmacológico , Aciclovir/farmacocinética , Administração Oral , Antivirais/farmacocinética , Resistência a Medicamentos , Infecções Oculares Virais/líquido cefalorraquidiano , Infecções Oculares Virais/virologia , Feminino , Herpes Genital/líquido cefalorraquidiano , Herpes Genital/virologia , Herpesvirus Humano 2/genética , Humanos , Recém-Nascido , Masculino , Doenças da Boca/líquido cefalorraquidiano , Doenças da Boca/virologia , Recidiva , Estudos Retrospectivos , Dermatopatias Virais/líquido cefalorraquidiano , Dermatopatias Virais/virologia
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