RESUMEN
BACKGROUND: We conducted a population-based study to evaluate whether non-small cell lung cancer (NSCLC) prognosis was worse in HIV-infected compared with HIV-uninfected patients. METHODS: Using the Surveillance, Epidemiology and End Results (SEER) registry linked to Medicare claims, we identified 267 HIV-infected patients and 1428 similar controls with no evidence of HIV diagnosed with NSCLC between 1996 and 2007. We used conditional probability function (CPF) analyses to compare survival by HIV status accounting for an increased risk of non-lung cancer death (competing risks) in HIV-infected patients. We used multivariable CPF regression to evaluate lung cancer prognosis by HIV status adjusted for confounders. RESULTS: Stage at presentation and use of stage-appropriate lung cancer treatment did not differ by HIV status. Median survival was 6 months (95% confidence interval (CI): 5-8 months) among HIV-infected NSCLC patients compared with 20 months (95% CI: 17-23 months) in patients without evidence of HIV. Multivariable CPF regression showed that HIV was associated with a greater risk of lung cancer-specific death after controlling for confounders and competing risks. CONCLUSION: NSCLC patients with HIV have a poorer prognosis than patients without evidence of HIV. NSCLC may exhibit more aggressive behaviour in the setting of HIV.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/complicaciones , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Infecciones por VIH/complicaciones , Infecciones por VIH/mortalidad , Neoplasias Pulmonares/complicaciones , Neoplasias Pulmonares/mortalidad , Anciano , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico , Carcinoma de Pulmón de Células no Pequeñas/patología , Femenino , Infecciones por VIH/diagnóstico , Humanos , Pulmón/patología , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Pronóstico , Programa de VERF , Tasa de Supervivencia , Estados UnidosRESUMEN
We demonstrate, for what we believe is the first time, recording of a femtosecond image hologram by illumination with a single pair of high-intensity femtosecond pulses in a broad inhomogeneous bandwidth spectral hole-burning material consisting of a polymer film doped with anthraceno-phthalocyanine dye molecules. High efficiency of spectral hole burning is achieved by preillumination of the sample at a low temperature to convert the dye molecules into an unstable tautomer form.
RESUMEN
Troglitazone and rosiglitazone (BRL49653), members of the thiazolidinedione (TZD) class of antidiabetic drugs, are peroxisome proliferator-activated receptor gamma (PPARgamma) ligands that induce adipocyte differentiation and increase the expression of PPARgamma protein. Here, we report the characterization of a PPARgamma specific monoclonal antibody (MAb), PgammaA53.25, and its use to monitor PPARgamma expression in the noncommitted pluripotent murine mesenchymal stem cell line, C3H10T1/2, treated with TZDs. MAb PgammaA53.25 was raised against a region in the N-terminal domain of human PPARgamma shared by splice variants PPARgamma1 and PPARgamma2. It recognizes immunizing antigen in enzyme-linked immunoadsorbent assay (ELISA), and does not cross-react with the N-terminal domains of PPARalpha or PPARdelta. In Western blotting, PgammaA53.25 reacts with the immunizing antigen as well as distinct protein bands corresponding to the molecular weight of full length PPARgamma from C3H10T1/2 cells and rat tissue lysates. In fluorescent microscopy, PgammaA53.25 immunostains nuclei of C3H10T1/2 cells treated with PPARgamma ligands. The fluorescence intensity of the treated cells is TZD dose-dependent, and correlates with lipid accumulation consistent with adipogenesis. Based on these results, we propose that MAb PgammaA53.25 will be a useful tool for elucidating the role of PPARgamma in fatty acid metabolism and adipocyte differentiation.
Asunto(s)
Anticuerpos Monoclonales , Cromanos/farmacología , Receptores Citoplasmáticos y Nucleares/biosíntesis , Receptores Citoplasmáticos y Nucleares/inmunología , Tiazoles/farmacología , Tiazolidinedionas , Factores de Transcripción/biosíntesis , Factores de Transcripción/inmunología , Adipocitos/citología , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Empalme Alternativo , Animales , Especificidad de Anticuerpos , Diferenciación Celular/efectos de los fármacos , Línea Celular , Humanos , Hibridomas/inmunología , Hipoglucemiantes/farmacología , Técnicas In Vitro , Ratones , Ratas , Receptores Citoplasmáticos y Nucleares/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Rosiglitazona , Especificidad de la Especie , Células Madre/citología , Células Madre/efectos de los fármacos , Células Madre/metabolismo , Factores de Transcripción/genética , TroglitazonaRESUMEN
The hypocholesterolemic activity for novel ureido fibrate analogues was found to be over 100-fold greater than for any "second-generation" fibrate in cholesterol-fed rats. A comparison of 12 related analogues revealed that the optimal configuration for a urea-bridging region located between two aromatic rings consisted of a trisubstituted nitrogen, optimally substituted with a C7 alkyl chain and linked by dimethylene to a phenoxyisobutyrate moiety found in most fibrate analogues. The hypocholesterolemic potency of these compounds was found to correlate with their increased intrinsic fibrate activity as determined by the ability to induce omega-hydroxylase activity either in rat hepatocyte cultures or in vivo, and not with their 10-fold increased ACAT inhibitory potency when compared to other fibrates. The most active compound, 2-(4-(2-(N'-(2,4- difluorophenyl)-N-heptylureido)ethyl)phenoxy)-2-methylpropionic acid, referred to as (2), was found to induce omega-hydroxylase activity in hepatocytes at concentrations between 5 and 100 nM compared to 1-20 microM concentrations for bezafibrate, and lower serum VLDL+LDL cholesterol in rats at doses between 0.1 and 0.5 mg/kg per day compared to doses of 25-100 mg/kg per day for bezafibrate. Single-dose pharmacokinetic studies with 2 indicated that total drug exposure will be much lower at hypocholesterolemic doses due to the enhanced intrinsic activity, and may result in an improved safety profile for these novel trisubstituted ureido fibrate analogues in rats and humans compared to other fibrates.
Asunto(s)
Bezafibrato/química , Bezafibrato/farmacología , Hipolipemiantes/química , Hipolipemiantes/farmacología , Esterol O-Aciltransferasa/antagonistas & inhibidores , Animales , Bezafibrato/farmacocinética , Butiratos/química , Butiratos/farmacología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Hipolipemiantes/farmacocinética , Hígado/citología , Hígado/enzimología , Hígado/metabolismo , Masculino , Concentración Osmolar , Compuestos de Fenilurea/química , Compuestos de Fenilurea/farmacología , Ratas , Ratas Sprague-Dawley , Esterol O-Aciltransferasa/metabolismo , Relación Estructura-ActividadRESUMEN
The spatial routing of a temporally encoded stream of optical pulses is experimentally demonstrated. The holograms that link the temporally shaped addresses to the def lection directions are engraved in a photorefractive crystal.
RESUMEN
During examination of the half-lives in cattle of a series of 5-substituted diaminobenzyl-pyrimidines, it was found that replacement of the phenyl ring of trimethoprim (TMP) by bicyclic structures, particularly a quinolyl group, led to increases in half-life. The presence of a dimethylamino group on the quinolyl ring of the compound baquiloprim (BQP) conferred a half-life of about 10 hours. In contrast to TMP (half-life about one hour), BQP was well absorbed from the gastrointestinal tract in all ages of cattle, plasma concentrations reaching a plateau on the day after dosing followed by a slow decline. BQP showed the same high broad spectrum antibacterial activity as TMP, with marked synergy with sulphonamides. Its differential binding of the dihydrofolate reductases of Escherichia coli and rat liver predicted a margin of safety similar to that of TMP. The results of efficacy studies in mice in comparison with TMP showed that the longer half-life of BQP was associated with greater efficacy, and therapeutic properties superior to those of TMP in cattle were therefore predicted for BQP.
Asunto(s)
Antibacterianos/farmacocinética , Bovinos/metabolismo , Antagonistas del Ácido Fólico/farmacocinética , Pirimidinas/farmacocinética , Administración Oral , Animales , Bacillus/efectos de los fármacos , Disponibilidad Biológica , Bovinos/microbiología , Escherichia coli/enzimología , Infecciones por Escherichia coli/prevención & control , Femenino , Semivida , Hígado/enzimología , Ratones , Ratones Endogámicos , Pruebas de Sensibilidad Microbiana/veterinaria , Pirimidinas/administración & dosificación , Pirimidinas/toxicidad , Ratas , Trimetoprim/toxicidadRESUMEN
The pharmacokinetics, metabolism, and qualitative tissue distribution of 502U83, a compound with antineoplastic activity, were examined in the rat. After an oral dose, average maximum plasma concentrations of 5.3 micrograms/ml were achieved at 0.28 hr, indicating rapid absorption of the compound; the bioavailability was estimated to be 62%. After intravenous administration the half-life was 1.73 hr. Autoradiographs of rats dosed intravenously with [14C]502U83 showed the presence of significant levels of radioactivity in the bone marrow, salivary gland, thymus, and lung; highest levels were in the gastrointestinal tract. There was no evidence of penetration of radioactivity into the brain. After an intravenous administration of [14C]502U83, a mean of 94.1% of the dose was recovered in 72 hr, with 46.6% in the urine and 47.5% in the feces. HPLC analysis of the radiocarbon in urine and feces revealed the presence of at least six common radioactive peaks, each representing approximately 2 to 12% of the dose. Biotransformation of 502U83 by the rat mainly involves oxidation of the hydroxyethyl group, and one or both of the hydroxymethyl groups leading to three major metabolites, common to urine and feces. Parent drug was the major component in both urine and feces, respectively, accounting for 18% and 10% of the dose in 48 hr. The glucuronic acid conjugate of the parent drug was a minor metabolite (< 2% of the dose). There was no evidence of metabolism on the anthracene ring.
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Antracenos/farmacocinética , Antineoplásicos/farmacocinética , Sustancias Intercalantes/farmacocinética , Animales , Antracenos/metabolismo , Antineoplásicos/metabolismo , Antineoplásicos/orina , Autorradiografía , Radioisótopos de Carbono , Heces/química , Femenino , Hidrólisis , Sustancias Intercalantes/metabolismo , Masculino , Ratas , Ratas Sprague-Dawley , Distribución TisularRESUMEN
The disposition of [14C]piritrexim ([14C]PTX) in male dogs after iv and po doses of 1.8 mg/kg was examined. After either route of administration, greater than 90% of the dose was recovered in the exreta within 72 hr; approximately 20% was recovered in urine and 70% in feces. [14C]PTX was extensively metabolized by dogs; unchanged drug accounted for less than 15% of the dose in the excreta. The O-demethylated metabolites, 2'- and 5'-demethyl PTX, the glucuronide conjugate of 2'-demethyl PTX, and the sulfate conjugate of 5'-demethyl PTX were the major metabolites. Unchanged drug accounted for a large proportion of the drug-related radiocarbon in plasma. The average plasma half-life of PTX after iv administration was 2.6 +/- 0.3 hr, and the average total body clearance was 0.33 +/- 0.13 liter/hr/kg. After po administration, peak plasma concentrations of 0.9 +/- 0.3 micrograms/ml occurred about 1.1 hr after the dose; the absolute oral bioavailability of PTX was 0.63 +/- 0.14. Because the O-demethyl metabolites were active dihydrofolate reductase inhibitors, 2'- and 5'-demethyl PTX were synthesized, and the pharmacokinetics and bioavailability of these compounds in dogs after iv and po administration (5 mg/kg) were examined. The plasma concentration-time data for both compounds after iv doses were described by a two-compartment model, with t1/2 beta = 1.3 and 0.8 hr for the 2'- and 5'- demethyl compounds, respectively. Neither compound showed significant advantages over PTX in terms of pharmacokinetics or bioavailability.
Asunto(s)
Antineoplásicos/farmacocinética , Pirimidinas/farmacocinética , Administración Oral , Animales , Antineoplásicos/sangre , Antineoplásicos/metabolismo , Disponibilidad Biológica , Radioisótopos de Carbono , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Perros , Heces/química , Inyecciones Intravenosas , Masculino , Piridinas/farmacocinética , Pirimidinas/sangre , Pirimidinas/metabolismo , Tetrahidrofolato Deshidrogenasa/sangreRESUMEN
Metabolism of the anticancer agent crisnatol was investigated using a human hepatoma cell line, Hep G2, and human liver microsomes. Crisnatol was metabolized extensively by both systems. The TLC/autoradiographic analysis showed that the crisnatol metabolite profile was similar for both systems and the major metabolites were shown to have structural characteristics similar to those formed by the rat. The Hep G2 cells formed three isomeric dihydrodiols; one of these has been identified by GC/MS and 1H-NMR as the crisnatol 1,2-dihydrodiol. Human liver microsomes also formed two isomeric dihydrodiols with 1,2-dihydrodiol as the major isomer and, in addition, produced 1-hydroxycrisnatol. Crisnatol concentrations of 1.3 micrograms/mL completely inhibited the replication of Hep G2 cells as measured by thymidine incorporation and cell growth kinetics and, at this concentration, cell viability decreased by only 35% as determined by vital staining of cells using neutral red dye.
Asunto(s)
Antineoplásicos/metabolismo , Carcinoma Hepatocelular/metabolismo , Crisenos/metabolismo , Neoplasias Hepáticas/metabolismo , Glicoles de Propileno/metabolismo , Autorradiografía , Carcinoma Hepatocelular/química , División Celular/efectos de los fármacos , Línea Celular , Cromatografía en Capa Delgada , Cromatografía de Gases y Espectrometría de Masas , Humanos , Neoplasias Hepáticas/química , Espectroscopía de Resonancia Magnética , Microsomas Hepáticos/metabolismo , Modelos Químicos , Rojo Neutro , Timidina/metabolismoRESUMEN
The disposition of [14C]piritrexim in male rats after iv (5 and 10 mg/kg) and po (5, 10, and 20 mg/kg) doses was studied. After an iv dose of 10 mg/kg, rats excreted an average of 57% of the dose in feces and 32% in urine; after a po dose of 10 mg/kg, 84% of the dose was excreted in feces and 9% in urine. After iv doses, the elimination of unchanged drug from plasma was first order, with a t1/2 of 0.6 hr; at any time point, unchanged drug accounted for less than 50% of the total radiocarbon in the plasma. Oral bioavailability of unchanged drug was less than 5%. O-Demethylation and subsequent conjugation were the main pathways of metabolism; the demethyl metabolites of piritrexim were potent inhibitors of dihydrofolate reductase and were cytotoxic to cells in culture. Concentrations of radiocarbon were highest in liver 24 hr after an iv dose, but less than 1% of the radiocarbon was unchanged drug. Concentrations of radiocarbon in liver after po doses were approximately 40% of those attained after equivalent iv doses.
Asunto(s)
Antagonistas del Ácido Fólico/farmacocinética , Pirimidinas/farmacocinética , Administración Oral , Animales , Disponibilidad Biológica , Biotransformación , Supervivencia Celular/efectos de los fármacos , Antagonistas del Ácido Fólico/administración & dosificación , Antagonistas del Ácido Fólico/metabolismo , Inyecciones Intravenosas , Radioisótopos de Yodo , Masculino , Pirimidinas/metabolismo , Pirimidinas/farmacología , Ratas , Tetrahidrofolato Deshidrogenasa/metabolismo , Distribución TisularRESUMEN
Disposition and metabolism of crisnatol (14C-labeled), a novel antitumor agent, was examined after po and iv administration to rats. After both routes of drug administration, there was rapid elimination of the administered radioactivity in the urine (6-12% of the dose) and feces (81-92% of the dose). The drug appeared to be rapidly absorbed after oral dose and there was substantial "first-pass" metabolism. Analysis of the excreta indicated extensive metabolism of crisnatol by the rat, with the intact compound being the major radiolabeled component in the feces (17-20% of dose). Intact drug was not present in urine. Biotransformation of crisnatol by the rat mainly involves oxidation and conjugation pathways. Hydroxylation and dihydrodiol formation in the chrysene ring and oxidation of the propanediol side chain resulted in the formation of the three major fecal metabolites. The principal metabolite in the urine was also a dihydrodiol. Concentrations of intact drug in each tissue assayed exceeded those in plasma, and in the lungs the tissue/plasma ratio approached 300 and 82 at 2 hr after iv and po doses, respectively.
Asunto(s)
Antineoplásicos/farmacocinética , Crisenos/farmacocinética , Glicoles de Propileno/farmacocinética , Animales , Antineoplásicos/metabolismo , Antineoplásicos/orina , Biotransformación , Cromatografía Líquida de Alta Presión , Crisenos/metabolismo , Crisenos/orina , Heces/química , Hidrólisis , Espectroscopía de Resonancia Magnética , Masculino , Glicoles de Propileno/metabolismo , Glicoles de Propileno/orina , Ratas , Ratas Endogámicas , Distribución TisularRESUMEN
Colors sampled in an array of pixels were converted into various luminance-chrominance representations, and the chrominance values were spatially subsampled to achieve a compression of the data. For viewing, the chrominance values were reinterpolated and then transformed back to RGB. For each of a range of image types and color spaces, we varied the chromatic sample spacing to determine how much compression would be possible before perceptual artifacts appeared, as determined by a panel of individual viewers. The spacing at which an image was mistaken half the time for a remembered original depended on image content and also on the color representation. Some color spaces, such as hue-lightness-saturation, a polar-coordinate color space, are inherently ill suited for chrominance averaging and produce noticeable artifacts on almost any image. Likewise, some images cannot be subsampled satisfactorily, regardless of the color space used. In general, however, images with 16-fold reduction in the amount of chrominance information (that is, a factor of 4 in each spatial direction) are still satisfactory in appearance.
Asunto(s)
Color , Procesamiento de Imagen Asistido por Computador , Percepción Visual/fisiología , Percepción de Color , Humanos , MatemáticaRESUMEN
Procedures for the simultaneous determination of trimethoprim (TMP) and sulfamethoxazole (SMX) in plasma or urine are reported. The drugs are extracted from plasma or urine by a single solid-phase extraction and quantitated by high-performance liquid chromatography. Both drugs are analyzed in the same chromatographic run. Intra- and interassay variability are less than 10% for both compounds, and the recovery and precision of TMP measurement are unaffected by concurrent SMX concentrations. Limits of quantitation for TMP and SMX in plasma were 0.02 and 0.21 microgram/ml, respectively. In urine, the limit of quantitation for both drugs was 1.0 microgram/ml. Metabolites of TMP and SMX did not interfere with the assay. Pharmacokinetic parameters from volunteers given two formulations of co-trimoxazole in a crossover comparison study are reported.
Asunto(s)
Sulfametoxazol/análisis , Trimetoprim/análisis , Disponibilidad Biológica , Cromatografía Líquida de Alta Presión/métodos , Humanos , Reproducibilidad de los Resultados , Espectrofotometría Ultravioleta/métodos , Sulfametoxazol/sangre , Sulfametoxazol/farmacocinética , Sulfametoxazol/orina , Trimetoprim/sangre , Trimetoprim/farmacocinética , Trimetoprim/orinaRESUMEN
A competitive protein binding assay for piritrexim (PTX, 1) that makes use of a commercially available radioassay kit for methotrexate has been developed. After it is selectively extracted from plasma, PTX competes with [125l]methotrexate for binding to dihydrofolate reductase isolated from Lactobacillus casei. Free drug is separated from bound drug by adsorption to dextran-coated charcoal. Piritrexim is measurable over a range of 0.01 to 10.0 micrograms/mL in plasma with a coefficient of variation less than 15%. The limit of sensitivity of the assay is approximately 2 ng/mL. An excellent correlation between this assay and a previously published HPLC method was found. published HPLC method was found.
Asunto(s)
Antineoplásicos/metabolismo , Pirimidinas/metabolismo , Unión Competitiva , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Antagonistas del Ácido Fólico , Humanos , Radioisótopos de Yodo , Unión ProteicaRESUMEN
A series of 2,4-diamino-5-(3,5-dialkenyl-4-methoxy- or -4-hydroxybenzyl)pyrimidines was prepared from [(allyloxy)benzyl]pyrimidines by Claisen rearrangements, and the resulting allyl phenols were further modified by methylation and rearrangement to 1-propenyl analogues. Analogous 3,4-dimethoxy-5-alkenyl derivatives were prepared by similar techniques. High in vitro antibacterial activity was obtained against certain anaerobic organisms, such as Bacteroides species and Fusobacterium, which was equal to or better than the control, metronidazole, in several cases. The profile was similar against Neisseria gonorrhoeae and Staphylococcus aureus. The 3,5-bis(1-propenyl)-4-methoxy derivative 8 was 1 order of magnitude more active against Escherichia coli dihydrofolate reductase than its saturated counterpart, and it was also more active than trimethoprim, 1. However, it was considerably less active in vitro against the Gram-negative organisms. The 3,4-dimethoxy-5-alkenyl, -5-alkyl, and -5-alkoxy analogues had very high broad-spectrum antibacterial activity. However, pharmacokinetic studies of four of the compounds in dogs and rats and in vivo studies with an abdominal sepsis model in rats showed no advantages over trimethoprim.
Asunto(s)
Alquenos/síntesis química , Antibacterianos/síntesis química , Bacterias Anaerobias/efectos de los fármacos , Pirimidinas/síntesis química , Alquenos/farmacocinética , Alquenos/farmacología , Animales , Antibacterianos/farmacocinética , Fenómenos Químicos , Química , Perros , Antagonistas del Ácido Fólico , Masculino , Pruebas de Sensibilidad Microbiana , Pirimidinas/farmacocinética , Pirimidinas/farmacología , Ratas , Ratas EndogámicasRESUMEN
Lipophilic analogues of trimethoprim (1) bearing 3,5-dialkyl-4-hydroxy substituents in the benzene ring are much more active in vitro against Neisseria gonorrhoeae than is 1. The 3,5-diisopropyl-4-hydroxy derivative (2) was selected as a candidate for clinical evaluation as an antigonococcal agent, and as part of the preliminary evaluation it was submitted to extended pharmacokinetic and metabolism studies in dogs. Although the compound was not extensively conjugated by metabolic enzymes, one of the methyl groups was metabolized to produce a 3-isopropyl-4-hydroxy-5-(alpha-carboxyethyl)benzyl derivative (43), which was rapidly excreted. Related analogues were likewise extensively metabolized.
Asunto(s)
Antibacterianos/síntesis química , Neisseria gonorrhoeae/efectos de los fármacos , Trimetoprim/análogos & derivados , Trimetoprim/síntesis química , Animales , Bacterias/efectos de los fármacos , Compuestos de Bencilo/síntesis química , Compuestos de Bencilo/farmacología , Perros , Femenino , Antagonistas del Ácido Fólico , Hígado/enzimología , Masculino , Pruebas de Sensibilidad Microbiana , Neisseria gonorrhoeae/enzimología , Pirimidinas/síntesis química , Pirimidinas/farmacocinética , Pirimidinas/farmacología , Ratas , Ratas Endogámicas , Trimetoprim/farmacocinética , Trimetoprim/farmacologíaRESUMEN
Piritrexim (PTX), 2,4-diamino-6-(2,5-dimethoxybenzyl)-5-methylpyrido[2,3-d]pyrimidin e, formerly called BW 301U, is a potent small-molecule inhibitor of dihydrofolate reductase (DHFR) that enters cells rapidly by passive diffusion and thus does not depend upon the transport-mediated uptake that can limit cell entry of methotrexate (MTX). PTX is as active as MTX in inhibiting DHFR and mammalian cell growth. In vivo, PTX is active against Walker 256, L1210, P388, Sarcoma 180, and Ehrlich ascites tumors. After iv administration of [14C]PTX to rats, the elimination profile of intact drug from plasma was first order with a half-life (t1/2) of 38 minutes. PTX penetrates extensively into tissues and its tissue:plasma concentration ratios are generally 10-fold higher than those reported for MTX. When administered systemically, PTX inhibits the DHFR-dependent conversion of sepiapterin or 7,8-dihydrobiopterin (BH2) to tetrahydrobiopterin (BH4), demonstrating that PTX enters brain at pharmacologically relevant concentrations. Pharmacokinetic studies in the dog indicated a mean plasma t1/2 (after iv dose) of 2.15 hours, total body clearance of 0.625 liters/hr/kg and steady-state volume of distribution of 1.82 liters/kg; the absolute bioavailability was 0.64. Toxicologic studies were conducted in rats and dogs that received daily doses for 1, 5, or 90 days. In dogs, oral doses of 480 (single dose), 25 (5 daily doses), and 2.5 mg/kg (90 daily doses) were lethal, whereas 240 (single dose), 2.5 (5 daily doses), and 0.5 mg/kg (90 daily doses) produced reversible alterations in clinical toxicity and histopathologic parameters. The lethal toxicity of PTX in dogs given 25 mg/kg/day for 5 days is prevented by oral calcium leucovorin rescue with either 0.75 or 3.0 mg/kg every hour for 4 hours on any of the 5 treatment days. The general pharmacologic profile indicates that PTX should be free of CNS, cardiovascular, and respiratory side effects at clinically useful doses.
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Antagonistas del Ácido Fólico , Pirimidinas/farmacología , Animales , Conducta Animal/efectos de los fármacos , Perros , Corazón/efectos de los fármacos , Tasa de Depuración Metabólica , Metotrexato/farmacocinética , Ratones , Músculo Liso/efectos de los fármacos , Neoplasias Experimentales/tratamiento farmacológico , Pirimidinas/farmacocinética , Pirimidinas/toxicidad , Ratas , Solubilidad , Distribución Tisular , Células Tumorales CultivadasRESUMEN
Recent advances in medical research have dramatically improved the survival rate for individuals with a history of cancer. Large numbers of these "cancer patient-returnees" encounter job discrimination since many employers believe that to hire or maintain them would pose substantial future business risks. This Note argues that cancer patient-returnees may seek relief under the Rehabilitation Act of 1973. The Note concludes that an employer's costs arising out of future risks are too insignificant to justify denial of job opportunities to cancer patient-returnees under the Act.
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Derechos Civiles/legislación & jurisprudencia , Empleo , Neoplasias/rehabilitación , Rehabilitación/legislación & jurisprudencia , Humanos , Riesgo , Estados UnidosRESUMEN
Specific methods using high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) for the analysis of the potent antifolate, 2,4-diamino-6-(2,5-dimethoxybenzyl)-5-methylpyrido-[2,3-d]pyrimidine (I) in plasma were developed. The HPLC system employed paired-ion chromatography using a mobile phase of water-acetonitrile (65:35, v/v) in conjunction with a reversed-phase C-1 column and detection by UV absorbance measurement. The TLC system utilized a scanning densitometer operating in the reflectance mode with detection of I by fluorescence measurement. The lower limits of detection for the HPLC and TLC methods were approximately 0.005 micrograms/ml. The coefficients of variation for the measurement of drug concentrations over the range of 0.04-1.0 microgram/ml of plasma were 5 and 6%, respectively.