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1.
Epidemiol Infect ; 147: e38, 2018 Nov 09.
Artículo en Inglés | MEDLINE | ID: mdl-30409242

RESUMEN

Japan is still a medium-burden tuberculosis (TB) country. We aimed to examine trends in newly notified active TB incidence and TB-related mortality in the last two decades in Japan. This is a population-based study using Japanese Vital Statistics and Japan Tuberculosis Surveillance from 1997 to 2016. We determined active TB incidence and mortality rates (per 100 000 population) by sex, age and disease categories. Joinpoint regression was applied to calculate the annual percentage change (APC) in age-adjusted mortality rates and to identify the years showing significant trend changes. Crude and age-adjusted incidence rates reduced from 33.9 to 13.9 and 37.3 to 11.3 per 100 000 population, respectively. Also, crude and age-adjusted mortality rates reduced from 2.2 to 1.5 and 2.8 to 1.0 per 100 000 population, respectively. Average APC in the incidence and mortality rates showed significant decline both in men (-6.2% and -5.4%, respectively) and women (-5.7% and -4.6%, respectively). Age-specific analysis demonstrated decreases in incidence and mortality rates for every age category, except for the incidence trend in the younger population. Although trends in active TB incidence and mortality rates in Japan have favourably decreased, the rate of decline is far from achieving TB elimination by 2035.

2.
Pharmazie ; 73(12): 740-743, 2018 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-30522561

RESUMEN

A history of hypertension is a known risk factor for delirium in patients in intensive care units, but the effect of antihypertensive agents on delirium development is unclear. Nicardipine, a calcium channel blocker, is widely used in ICU as a treatment agent for hypertensive emergency. This study investigated the relationship between the administration of nicardipine hydrochloride and delirium development in patients under mechanical ventilation. We conducted a medical chart review of 103 patients, who were divided into two groups according to the use of nicardipine hydrochloride. The prevalence of delirium was compared with respect to factors such as age, sex, laboratory data, and medical history, by multivariate analysis. 21 patients (20.4 %) were treated with nicardipine hydrochloride in 103 patients. The treatment and non-treatment groups differed significantly in age (72 vs. 65 years) and history of high blood pressure (57% vs. 11%). Multivariate analysis revealed that patients in the treatment group developed delirium significantly less often than those in the non-treatment group (19% vs. 48%). These results suggested that treatment of high blood pressure with nicardipine hydrochloride is a possible method for preventing the development of delirium.


Asunto(s)
Delirio/epidemiología , Hipertensión/tratamiento farmacológico , Nicardipino/administración & dosificación , Respiración Artificial , Adulto , Anciano , Anciano de 80 o más Años , Antihipertensivos/administración & dosificación , Antihipertensivos/farmacología , Bloqueadores de los Canales de Calcio/administración & dosificación , Bloqueadores de los Canales de Calcio/farmacología , Delirio/etiología , Delirio/prevención & control , Femenino , Humanos , Hipertensión/complicaciones , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Nicardipino/farmacología , Prevalencia , Estudios Retrospectivos , Factores de Riesgo
3.
J Clin Pharm Ther ; 34(4): 415-22, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19583674

RESUMEN

OBJECTIVE: To characterize the relationship between total and unbound concentrations of valproic acid (VPA) in epileptic neonates and infants, the clinical examination records of those patients archived via therapeutic drug monitoring (TDM) activities were retrospectively analyzed. METHODS: The screening encompassed 249 records of 114 epileptic patients aged 0-19 years old, who were treated with VPA monotherapy and whose total and unbound VPA concentrations were determined. These data were divided into groups according to the patients' age. In each group, the relationship between total and unbound VPA concentrations was compared to a reference profile, and the deviation from the reference was evaluated. The reference profile was calculated using the Langmuir equation, in which two parameters Kd and Bm were set to 7.8 and 130 microg/mL, respectively, according to our previous findings. RESULTS: The relationship between total and unbound VPA concentrations of patients of 0 years old considerably deviated from the reference, and their unbound VPA concentrations were generally higher compared to the corresponding reference values. It is suggested that the large deviation is related to the fact that the serum albumin concentrations of patients younger than 1 year old tend to be lower than those of patients in other age groups. CONCLUSION: Since the relationship between the VPA concentrations of epileptic neonates and infants is noticeably different from the reference, the unbound serum VPA concentrations of these patients are not adequately estimated using the same method as that for grown-ups. The unbound VPA concentrations of neonates and infants should be explicitly determined via TDM activities.


Asunto(s)
Anticonvulsivantes/farmacocinética , Monitoreo de Drogas/métodos , Epilepsia/tratamiento farmacológico , Ácido Valproico/farmacocinética , Adolescente , Adulto , Factores de Edad , Anticonvulsivantes/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Unión Proteica , Valores de Referencia , Estudios Retrospectivos , Albúmina Sérica/metabolismo , Ácido Valproico/uso terapéutico , Adulto Joven
4.
Int J Clin Pharmacol Ther ; 46(11): 584-90, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19000557

RESUMEN

OBJECTIVE: Oral mucositis is a major toxicity in the high-dose methotrexate (HD-MTX) treatment for children with acute lymphoblastic leukemia (ALL). The first aim of this study was to evaluate the relationship between the MTX serum concentration and occurrence of oral mucositis in pediatric ALL patients. The second aim was to clarify the relationship between MTX exposure and epidermal keratinocyte cell injury using an in vitro study. METHODS: 49 patients were treated according to the Japan Association of Childhood Leukemia Study (JACLS) ALL-HR02 protocol. This protocol involves HD-MTX treatment (3 g/m2 for 24-h i.v. infusion). The MTX serum concentrations were measured by a fluorescence polarization immunoassay. The relationship between oral mucositis and MTX serum concentrations 48 and 72 h after administration was determined. The cell toxicity of MTX for human epidermal keratinocytes was analyzed by using a cell viability assay (WST-1 assay). In addition, pharmacokinetic evaluation for clearance, AUC extrapolated from 48 h to infinity (AUC48h-inf) and elimination half-life (t1/2b) were done using the 1-compartmental models. RESULTS: Oral mucositis occurred in 24 patients (49.0%), in whom 20 patients (83.3% in oral mucositis group) showed WHO severity Grade 1 or 2. Only 4 patients (16.7% in oral mucositis group) showed Grade 3 severity. 22 patients (44.9%) had oral mucositis in the group with a concentration under 10-6 M 48 h after MTX administration. There was no significant deference among the cell viabilities in the concentrations of 10-6 M, 10-5 M and 10-4 M 48 h after the MTX exposure. However, the cell viability obtained 24 h after the MTX exposure was significantly different from the respective cell viability 48, 72 and 96 h after the MTX exposure. In the group with oral mucositis, the clearance decreased significantly (p = 0.042), and the t1/2b (p = 0.025) and AUC48h- yen (p = 0.025) increased significantly compared with the non-symptom group. CONCLUSIONS: It seems that there is no significant relationship between the serum MTX concentration and oral mucositis. This in vitro study has demonstrated that the cell injury was related to the duration of MTX exposure rather than a high MTX concentration.


Asunto(s)
Antimetabolitos Antineoplásicos/efectos adversos , Antimetabolitos Antineoplásicos/uso terapéutico , Queratinocitos/efectos de los fármacos , Metotrexato/efectos adversos , Metotrexato/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Estomatitis/inducido químicamente , Adolescente , Antimetabolitos Antineoplásicos/farmacocinética , Área Bajo la Curva , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Niño , Preescolar , Relación Dosis-Respuesta a Droga , Femenino , Semivida , Humanos , Lactante , Masculino , Tasa de Depuración Metabólica , Metotrexato/farmacocinética
5.
J Clin Pharm Ther ; 33(1): 31-8, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18211614

RESUMEN

OBJECTIVE: To establish a regression equation to properly estimate the unbound serum concentration of valproic acid (VPA) from its total serum concentration; the relationship between total and unbound serum VPA concentrations was retrospectively characterized. METHODS: Data were obtained from the clinical examination records that were routinely archived during therapeutic drug monitoring. The screening encompassed 342 records of 108 paediatric patients whose total and unbound VPA concentrations had been determined. The relationship between total and unbound VPA concentrations was characterized according to the Langmuir equation by taking account of inter-individual variability with the nonmem program. RESULTS: The total VPA concentration (C(t)) in the screened patients ranged from 5.5 to 179.8 microg/mL, and the unbound VPA concentration (C(f)) increased in a non-linear manner as the total VPA concentration increased. Taking account of the effects of antiepileptics concurrently administered, the VPA dissociation constant (K(d)) and maximum binding site concentration (B(m)) were 7.8 +/- 0.7 and 130 +/- 4.5 microg/mL respectively, for the regression equation, C(t) = C(f) + B(m) x C(f)/(K(d) + C(f)). An alteration in the unbound concentration was seen in patients who were treated with the combination of VPA and ethosuximide and in those who received two additional antiepileptics. CONCLUSIONS: A regression equation for estimation of the unbound VPA concentration, based on total VPA concentration collected during routine therapeutic drug monitoring was established. Use of two additional antiepileptics and ethosuximide treatment was considered as potential factors affecting unbound VPA concentration.


Asunto(s)
Anticonvulsivantes/farmacocinética , Epilepsia/tratamiento farmacológico , Ácido Valproico/farmacocinética , Adolescente , Anticonvulsivantes/farmacología , Sitios de Unión , Niño , Preescolar , Interacciones Farmacológicas , Monitoreo de Drogas , Quimioterapia Combinada , Etosuximida/farmacología , Humanos , Lactante , Dinámicas no Lineales , Unión Proteica , Análisis de Regresión , Estudios Retrospectivos
6.
Invest Radiol ; 35(8): 472-8, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10946974

RESUMEN

RATIONALE AND OBJECTIVES: Nitric oxide (NO) regulation of endothelial function is involved in the development of acute lung injury. The role of NO in contrast media-induced increases in pulmonary vascular permeability was investigated in a rat model. METHODS: Nonionic (iohexol) and ionic (ioxaglate) contrast media were intravenously injected at 1.5 mL/min in rats. Pulmonary vascular permeability was evaluated by measuring the amount of Evans blue dye uptake as a quantitative marker of albumin extravasation in lung tissue. RESULTS: Intravenous injections of contrast media at doses of 4 and 6 g I/kg induced a dose-dependent increase in pulmonary vascular permeability. L-Arginine (an NO synthase substrate) and N(G)-nitro-L-arginine (L-NNA) (an NO synthase inhibitor) prevented and aggravated, respectively, the increase in pulmonary vascular permeability induced by the contrast medium. An aggravating action of L-NNA was confirmed by morphological and histological observations, this action being blocked by L-arginine (300 mg/kg) but not by D-arginine. Isosorbide dinitrate (1-20 mg/kg), an NO donor, had a dose-dependent protective effect on ioxaglate-increased vascular permeability. CONCLUSIONS: Our experimental findings suggest that contrast media at high doses produce pulmonary edema by inhibiting endothelial NO production, and nitrovasodilators protect against this adverse effect in rats.


Asunto(s)
Permeabilidad Capilar/efectos de los fármacos , Medios de Contraste/efectos adversos , Dinitrato de Isosorbide/farmacología , Óxido Nítrico/fisiología , Edema Pulmonar/inducido químicamente , Vasodilatadores/farmacología , Animales , Arginina/farmacología , Medios de Contraste/administración & dosificación , Inhibidores Enzimáticos/farmacología , Inyecciones Intravenosas , Yohexol/administración & dosificación , Yohexol/efectos adversos , Ácido Yoxáglico/administración & dosificación , Ácido Yoxáglico/efectos adversos , Masculino , Óxido Nítrico/biosíntesis , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroarginina/farmacología , Edema Pulmonar/patología , Edema Pulmonar/prevención & control , Ratas , Ratas Sprague-Dawley
7.
Invest Radiol ; 36(3): 131-5, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11228576

RESUMEN

UNLABELLED: Tominaga K, Kataoka Y, Sendo T, et al. Contrast medium-induced pulmonary vascular hyperpermeability is aggravated in a rat climacterium model. Invest Radiol 2001;36:131-135. RATIONALE AND OBJECTIVES: To test whether climacterium influences adverse pulmonary reactions to contrast media, the authors investigated the effect of ioxaglate on pulmonary vascular permeability in ovariectomized rats as a climacterium model. METHODS: From 7 days after surgery, ovariectomized rats were treated with estradiol valerate or vehicle once per week for 3 weeks. At 28 days after surgery, ioxaglate, an ionic contrast medium, was intravenously injected at 1.5 mL/min in rats. Pulmonary vascular permeability was evaluated by measuring the amount of Evans blue dye in the lung tissue. RESULTS: Ioxaglate dose-dependently increased pulmonary vascular permeability in sham-operated and ovariectomized rats. Ovariectomized rats showed a 2.6-fold increased aggravation of vascular permeability by ioxaglate 4 g I/kg compared with sham-operated rats. Estradiol valerate (0.2-5.0 mg/kg) dose-dependently blocked ioxaglate-increased vascular permeability in ovariectomized rats. CONCLUSIONS: These findings suggest that climacterium is included, at least in part, in the risk factors for contrast-induced adverse pulmonary reactions, and this risk is lowered by estrogen replacement therapy.


Asunto(s)
Permeabilidad Capilar/efectos de los fármacos , Climaterio , Medios de Contraste/efectos adversos , Medios de Contraste/farmacocinética , Extravasación de Materiales Terapéuticos y Diagnósticos/etiología , Modelos Animales , Arteria Pulmonar , Animales , Femenino , Ratas , Ratas Wistar , Índice de Severidad de la Enfermedad
8.
Toxicol Lett ; 31(2): 131-7, 1986 May.
Artículo en Inglés | MEDLINE | ID: mdl-3520960

RESUMEN

Hydrazine (Hz) mutagenicity was observed in a test using Escherichia coli B/r strain, WP2 uvrA and was enhanced by the addition of rat liver microsomal fraction containing a generating system, while the enhanced mutagenicity was diminished by the addition of metyrapone to the microsome-free levels. On the other hand, an NADPH-dependent difference spectrum of the metabolic intermediate of Hz-complex, characterized by a maximum level of 448 nm, was also inhibited by metyrapone. The results show that the oxidative intermediates, which are diimide and its precursor, hydrazine free radical [Biochem. Biophys. Res. Commun., 133 (1986) 1086], are responsible not only for hepatotoxicity but also for the enhancement of genotoxicity or mutagenicity.


Asunto(s)
Hidrazinas/toxicidad , Microsomas Hepáticos/efectos de los fármacos , Mutágenos , Animales , Escherichia coli , Hidrazinas/antagonistas & inhibidores , Hidrazinas/metabolismo , Masculino , Metirapona/farmacología , Microsomas Hepáticos/metabolismo , Pruebas de Mutagenicidad , Oxidación-Reducción , Fenobarbital/farmacología , Ratas , Ratas Endogámicas
9.
Toxicol Lett ; 25(3): 313-7, 1985 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-4012807

RESUMEN

After the intraperitoneal (i.p.) administration of isoniazid (INH) to male Wistar rats, the liver and plasma levels of hydrazine (Hz) and acetylhydrazine (AcHz), which are hazardous metabolites of INH and well known as mutagens, carcinogens and hepatotoxins, were determined by gas chromatography-mass spectrometry (GC-MS). The levels of Hz in rifampicin (RMP)- or phenobarbital (PB)-pretreated groups were lower than those in the control group, while the amount of AcHz was scarcely altered. In each of the pretreated groups a pronounced increase in the oxidative elimination rate of Hz was observed. These results are of important toxicological significance in INH therapy with RMP, since an active intermediate of Hz seems to be a hepatotoxin.


Asunto(s)
Hidrazinas/metabolismo , Isoniazida/metabolismo , Fenobarbital/farmacología , Rifampin/farmacología , Acetilación , Animales , Interacciones Farmacológicas , Hígado/metabolismo , Masculino , Oxidación-Reducción , Ratas , Ratas Endogámicas
10.
Acad Radiol ; 8(2): 158-61, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11227644

RESUMEN

RATIONALE AND OBJECTIVES: The purpose of this study was to characterize the adverse effects of iohexol and ioxaglate on human microvascular endothelial cells, which may result in phlebitis, pain, and thrombosis. MATERIALS AND METHODS: The degree of morphologic degeneration and of lactate dehydrogenase (LDH) efflux into the extracellular medium (as an index of cell viability) were determined in endothelial cell culture exposed for 10, 30, or 60 minutes to ioxaglate or iohexol (ionic and nonionic contrast media, respectively) at iodine concentrations of 100 or 150 mg/mL. RESULTS: Ioxaglate induced concentration- and time-dependent morphologic degeneration, including shrinkage and loss of the cell tip in 20%-80% of endothelial cells; iohexol did not. After 60 minutes of exposure, ioxaglate at the higher concentration (150 mg iodine per milliliter) significantly increased the LDH signal (ie, the percentage of LDH released), to 20%. CONCLUSION: The present findings demonstrate that ioxaglate but not iohexol causes morphologic degeneration of the microvascular endothelial cells. This direct cytotoxic action of ioxaglate probably causes endothelial cell dysfunction, closely associated with the occurrence of phlebitis, pain, and thrombosis.


Asunto(s)
Medios de Contraste/efectos adversos , Endotelio Vascular/efectos de los fármacos , Yohexol/efectos adversos , Ácido Yoxáglico/efectos adversos , Células Cultivadas , Endotelio Vascular/citología , Humanos , L-Lactato Deshidrogenasa/metabolismo , Pulmón/citología , Factores de Tiempo
11.
Acad Radiol ; 5(6): 444-7, 1998 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9615155

RESUMEN

RATIONALE AND OBJECTIVES: The authors compared the particle contaminations of radiographic contrast media packaged in large-volume prefilled syringes and vials. MATERIALS AND METHODS: Particle counting was performed for four contrast media packaged in large-volume prefilled syringes (iohexol, ioversol, ioversol for angiography, and ioxaglate) and three contrast media packaged in vials (iohexol, ioversol, and ioxaglate). X-ray emission spectrometry was performed to characterize the individual particles. The amount of silicone oil in the syringe was quantified with infrared spectrophotometry. RESULTS: The particle contamination in syringes containing ioversol was higher than that in syringes containing iohexol or ioxaglate. Particle contamination in the vials was relatively low, except with ioxaglate. X-ray emission spectrometry of the components of the syringe and vial showed that the source of particles was internal material released from the rubber stopper or inner surface. CONCLUSION: The particle counts for contrast media packaged in syringes and vials varied considerably among the different contrast media and were related to the amount of silicone oil on the inner surface and rubber piston of the syringe.


Asunto(s)
Medios de Contraste/química , Contaminación de Medicamentos , Goma/análisis , Aceites de Silicona/análisis , Jeringas , Embalaje de Medicamentos , Microscopía Electrónica de Rastreo , Control de Calidad , Espectrometría por Rayos X , Espectrofotometría Infrarroja
12.
Br J Radiol ; 72(862): 998-9, 1999 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10673952

RESUMEN

In a study of exogenous particulate contamination during angiography, the effect of injection speed of four kinds of radiographic contrast media (RCM) was investigated. The particle count (> or = 10 microns) in all RCM increased in a speed-dependent manner and the increase was especially dramatic at 3 ml s-1. The extent of increase in particulate matter was higher for ioxaglate than for the other three RCM. As particulate matter is unwanted and unnecessary, to prevent the harmful effects in patients much attention should be paid to various factors generating particulate matters, such as characteristics of RCM and plastic syringe.


Asunto(s)
Angiografía , Medios de Contraste/administración & dosificación , Contaminación de Medicamentos , Tomografía Computarizada por Rayos X , Esquema de Medicación , Humanos , Inyecciones Intravenosas , Jeringas
13.
PDA J Pharm Sci Technol ; 49(6): 267-71, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-8581457

RESUMEN

Our evaluation of electronic liquid-borne particle counter systems has shown that, for accurate measurement of particulate matter in injections, the half count values of voltage thresholds from the particle counter itself should be used in the calibration for the particle sizes being evaluated. The manual method which uses the half count values in the USP XXIII<788> was improved, and the validity of our calibration method was supported by the results based on the ratio test, at 10 microns to those obtained at 15 microns is between 1.5 and 3.5, as per the Seventh Supplement of USP XXII <788>. Additionally, computer-based systems with automated calibration routines which solve the approximate Gaussian distribution of calibration particles have advantages. For the proper determination of the sizing accuracy of a particle counter, criteria of the ratio test at 10 microns and 15 microns as per the Seventh Supplement of USP XXII <788> should be applied at all critical particle sizes.


Asunto(s)
Calibración/normas , Tamaño de la Partícula , Tecnología Farmacéutica/instrumentación , Simulación por Computador , Distribución Normal , Estándares de Referencia
14.
J UOEH ; 6(3): 249-55, 1984 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-6494651

RESUMEN

The characteristics of isoniazid amidase which hydrolyzes isoniazid to isonicotinic acid and hydrazine was examined in vitro using rat liver subcellular fractions. The activity of isoniazid amidase was estimated from the amount of hydrazine produced from a substrate, isoniazid, by means of GC-MS. High activity of the amidase was observed in the microsomal and lysosomal fractions, and at pH 7.4-7.8 in the microsomal fraction. The amidase was not inhibited by acetanilide, but by procaine and bis(p-nitrophenyl)phosphate. As expected, acetylisoniazid, a main metabolite of isoniazid, also inhibited the amidase. Not only the microsomal monooxygenase but also amidase was strongly induced by pretreatment with phenobarbital, 3-methylcholanthrene and rifampicin, respectively.


Asunto(s)
Amidohidrolasas/metabolismo , Isoniazida/metabolismo , Hígado/enzimología , Animales , Técnicas In Vitro , Inactivación Metabólica , Masculino , Ratas , Ratas Endogámicas , Fracciones Subcelulares/enzimología
16.
Kidney Int ; 69(2): 288-97, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16408118

RESUMEN

We reported previously that various radiocontrast media cause apoptosis in porcine proximal tubular (LLC-PK(1)) cells, in which reduction in B-cell lymphoma (Bcl)-2 expression and caspase-3 activation are implicated. In the present study, we investigated a role for ceramide in radiocontrast media-induced apoptosis in renal tubular cells. LLC-PK(1) cells were exposed to radiocontrast media for 30 min, followed by incubation for 24 h in normal medium. Cell viability was assessed by 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt assay, while apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling stain. Immunofluorescent stains were performed using antibodies against phosphorylated Akt (pAkt) and cAMP response element binding protein (CREB) (pCREB), and ceramide. The mRNA expression and protein content of Bcl-2 were determined by reverse transcriptase-polymerase chain reaction and enzyme immunoassay, respectively. In vivo model of contrast-induced renal injury was induced in mice with unilateral renal occlusion. The cell injury induced by the nonionic radiocontrast medium ioversol was reversed by inhibiting de novo ceramide synthesis with fumonisin B(1) (FB(1)) and L-cycloserine, but not by suppressing sphingomyelin breakdown with D609. FB(1) reversed ioversol-induced decrease in the immunoreactivities of pAkt and pCREB, reduction in Bcl-2 expression and caspase-3 activation. Like ioversol, C2 ceramide and the Akt inhibitor Src homology-6 induced apoptosis by reducing pAkt and pCREB-like immunoreactivities, lowering Bcl-2 expression and enhancing caspase-3 activity. Indeed, various radiocontrast media, excluding iodixanol which showed the least nephrotoxicity, enhanced ceramide-like immunoreactivity. The role for de novo ceramide synthesis was also shown in the in vivo model of radiocontrast nephropathy. We demonstrated here for the first time that the enhancement of de novo ceramide synthesis contributes to radiocontrast nephropathy.


Asunto(s)
Ceramidas/biosíntesis , Medios de Contraste/toxicidad , Túbulos Renales/efectos de los fármacos , Ácidos Triyodobenzoicos/toxicidad , Acetilglucosamina/orina , Animales , Apoptosis , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Fumonisinas/farmacología , Factor I del Crecimiento Similar a la Insulina/farmacología , Túbulos Renales/patología , Ratones , Mitocondrias/efectos de los fármacos , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/análisis , Proteínas Proto-Oncogénicas c-bcl-2/genética , Especies Reactivas de Oxígeno , Porcinos
17.
Pharm Res ; 12(1): 18-23, 1995 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-7724483

RESUMEN

The efficacy and toxicity of vitamin K depends on the pathway and the extent of enzymatic reductive activation to vitamin K hydroquinone, which is an essential cofactor for the synthesis of clotting factors. Parenteral use of vitamin K is impaired by its water insolubility. With the aim to improve delivery problems associated with menahydroquinone-4 (MKH, 2), an active form of menaquinone-4, N,N-dimethylglycine esters of 2 (1-mono, 4-mono, and 1,4-bis) were synthesized and assessed as potential water-soluble prodrugs for parenteral use. The esters can deliver the hydroquinone to its active site without a quinone reductive activation step. The hydrochloride salts of the esters were found to be quite soluble in water. The hydrolysis of the esters in 20% rat liver homogenate 9000 x g supernatant, rat plasma and phosphate buffer, pH 7.4, at 37 degrees C was kinetically studied in the presence and absence of an esterase inhibitor. The hydrolysis was catalyzed by esterases located in the rat liver and rat plasma and quantitatively yielded 2. These results suggest that esterification of 2 with N,N-dimethylglycine is a promising way for obtaining water-soluble prodrug forms of 2. Based on the high susceptibility to liver esterase, the esters are potential prodrugs for achieving the site-specific delivery of 2.


Asunto(s)
Ésteres/síntesis química , Ésteres/farmacocinética , Hidroquinonas/síntesis química , Hidroquinonas/farmacocinética , Profármacos/síntesis química , Profármacos/farmacocinética , Vitamina K 2/análogos & derivados , Vitamina K/análogos & derivados , Vitamina K/farmacocinética , Animales , Biotransformación , Fenómenos Químicos , Química Física , Diseño de Fármacos , Esterasas/antagonistas & inhibidores , Ésteres/química , Hidrólisis , Hidroquinonas/química , Infusiones Parenterales , Cinética , Lípidos/química , Profármacos/química , Ratas , Solubilidad , Vitamina K/síntesis química , Vitamina K/química , Vitamina K/metabolismo , Agua/química
18.
J Ocul Pharmacol ; 4(4): 335-43, 1988.
Artículo en Inglés | MEDLINE | ID: mdl-3246568

RESUMEN

Ocular absorption of timolol in rabbits was studied after topical ocular administration of 3H-timolol in an eyedrop or in silicone cylindrical devices that released timolol at 7.2 micrograms/h. The devices were applied in either the inferior or superior conjunctival sac. Timolol concentrations were nearly equal in the inferior and superior portions of ocular tissues when the drug was administered in an eyedrop. Administration in the devices resulted in unequal timolol distribution in the cornea, conjunctiva, sclera, and iris-ciliary body. Timolol concentrations were higher in the part of each tissue that was closer to the site of the device application. Unequal concentrations of timolol in the superior and inferior part of the eye and very low timolol concentrations in the aqueous humor indicated that timolol was absorbed mainly via a noncorneal route from the device placed in the inferior conjunctival sac. Induced blinking at one minute intervals did not change ocular absorption of timolol. Compared with inferior conjunctival sac applications, placement of the devices in the superior conjunctival sac resulted in increased corneal and total ocular absorption of timolol as indicated by higher timolol concentrations in the aqueous humor and by a smaller difference between concentrations in the superior and inferior portions of the examined tissues. The application site dependent ocular absorption indicated that controlled release of timolol in the tear fluid did not result in a uniform timolol distribution in the preocular tear fluid of rabbit eyes.


Asunto(s)
Ojo/metabolismo , Timolol/farmacocinética , Absorción , Administración Tópica , Animales , Cuerpo Ciliar/metabolismo , Conjuntiva/metabolismo , Córnea/metabolismo , Vías de Administración de Medicamentos , Iris/metabolismo , Conejos , Esclerótica/metabolismo , Timolol/administración & dosificación , Cuerpo Vítreo/metabolismo
19.
Pharm Res ; 12(12): 1973-9, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8786976

RESUMEN

PURPOSE: The hydrochloride salts of the N,N-dimethylglycine esters of menahydroquinone-4 (1-mono, 1; 4-mono, 2; and 1,4-bis, 3) were assessed in vivo as prodrug for the systemic site-specific delivery system of menahydroquinone-4 (MKH), the active form of menaquinone-4 (MK-4, vitamin K2(20)). METHODS: The disposition of MK-4 and menaquinone-4 epoxide (MKO) following the intravenous administration of the prodrugs and MK-4 preparation solubilized with surfactant (H-MK-4) were studied in vitamin K cycle inhibited rats. The relative bioavailability of MKH after the administration of the prodrugs was assessed from the area under the plasma concentration of MKO vs. time curve (AUCMKO). The specific delivery of MKH to its active site (liver) and coagulation activity after the administration of selected prodrug 1 were then compared with those of H-MK-4 in warfarin poisoned rats. RESULTS: All compounds showed linear pharmacokinetics, and significant bioavailability of MKH was also observed following the administration of 1 (188%), 2 (87%) and 3 (135%). Prodrug 1 caused the following increases; AUCliver of MKO from 70.7 +/- 5.77 (H-MK-4) to 167 +/- 7.89 nmol.h/g, MRTliver of MKO, from 3.87 +/- 0.307 to 8.57 +/- 0.432 h. The liver accumulation of intrinsic 1 reached a maximum (88% of dose) by 0.25 h. The rapid and liver-selective uptake and liver esterase mediated MKH regeneration characteristics of 1 enhanced the delivery of MKH to its active site and the selective advantage was increased 5.7 fold. The coagulation activity was extended 1.9 fold by 1 administration. CONCLUSIONS: The results indicated that these highly water-soluble and liver-esterase hydrolyzable ester derivatives of MKH are potential candidates for parenteral prodrugs which can thus achieve the systemic site-specific delivery of MKH. Such effective and selective delivery of MKH to its active site can therefore lead to enhanced pharmacological efficacy and can also avoid the toxicity induced by the solubilizing agent used in the H-MK-4 preparation.


Asunto(s)
Sistemas de Liberación de Medicamentos , Hidroquinonas/metabolismo , Profármacos/metabolismo , Vitamina K 2/análogos & derivados , Vitamina K/análogos & derivados , Vitamina K/metabolismo , Animales , Relación Dosis-Respuesta a Droga , Hidroquinonas/farmacocinética , Masculino , Ratas , Ratas Wistar , Vitamina K/farmacocinética , Warfarina/farmacología
20.
Biol Pharm Bull ; 18(12): 1793-6, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8787812

RESUMEN

The quality of three commercial injections (Genotropin, Humatrope and Norditropin) of lyophilized recombinant human growth hormone (r-hGH) was evaluated in tests by visual inspection, high-performance gel permeation chromatography, polyacrylamide gel electrophoresis, scanning electron microscopy and energy dispersion X-ray microanalysis. The influence of the reconstitution method on gel formation was examined as follows: rapid injection of the diluting solution into a vial against the wall, slow injection onto the surface of the content, and rapid injection onto the surface of the content. The degree of gel formation differed among reconstitution methods. Moreover, fibrous particulate matter in addition to degradation products of r-hGH were evident in all preparations. The quality of r-hGH injection differed among commercial products. Norditropin included the least particulate matter when examined immediately after reconstitution, but it was easily denatured after storage in solution. We advise medical specialists to reconstitute a preparation by the optimal method.


Asunto(s)
Contaminación de Medicamentos , Hormona del Crecimiento/análisis , Composición de Medicamentos , Liofilización , Humanos , Control de Calidad , Proteínas Recombinantes/análisis
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