Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 19 de 19
Filtrar
1.
Food Chem Toxicol ; 134 Suppl 2: 111024, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31812735

RESUMEN

Hydroxycitronellal dimethyl acetal was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog hydroxycitronellal diethyl acetal (CAS # 7779-94-4) show that hydroxycitronellal dimethyl acetal is not expected to be genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class I material and the exposure to hydroxycitronellal dimethyl acetal is below the TTC (0.03 mg/kg/day, 0.03 mg/kg/day, and 1.4 mg/day, respectively). Data from hydroxycitronellal dimethyl acetal and from read-across material hydroxycitronellal diethyl acetal (CAS # 7779-94-4) show that there are no safety concerns for skin sensitization under the current declared levels of use. The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; hydroxycitronellal dimethyl acetal is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; hydroxycitronellal dimethyl acetal was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Asunto(s)
Acetales/toxicidad , Octanoles/toxicidad , Odorantes , Acetales/química , Animales , Seguridad de Productos para el Consumidor , Evaluación Preclínica de Medicamentos , Determinación de Punto Final , Escherichia coli/efectos de los fármacos , Humanos , Pruebas de Mutagenicidad , Nivel sin Efectos Adversos Observados , Octanoles/química , Medición de Riesgo , Salmonella typhimurium/efectos de los fármacos
2.
Food Chem Toxicol ; 134 Suppl 2: 111002, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31785315

RESUMEN

The existing information supports the use of this material as described in this safety assessment. p-Tolyl acetate was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog ethyl p-tolyl carbonate (CAS # 22719-81-9) show that p-tolyl acetate is not expected to be genotoxic. Data on read-across materials p-cresol (CAS # 106-44-5) and acetic acid (CAS # 64-19-7) provide a calculated MOE >100 for the repeated dose and reproductive toxicity endpoints. The skin sensitization endpoint was completed using DST for reactive materials (64 µg/cm2); exposure is below the DST. The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; p-tolyl acetate is not expected to be phototoxic/photoallergenic. The local respiratory toxicity endpoint was evaluated using the TTC for a Cramer Class I material, and the exposure to p-tolyl acetate is below the TTC (1.4 mg/day).The environmental endpoints were evaluated; p-tolyl acetate was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Asunto(s)
Cresoles/toxicidad , Odorantes , Animales , Seguridad de Productos para el Consumidor , Cresoles/química , Evaluación Preclínica de Medicamentos , Determinación de Punto Final , Escherichia coli/efectos de los fármacos , Humanos , Pruebas de Mutagenicidad , Nivel sin Efectos Adversos Observados , Medición de Riesgo , Salmonella typhimurium/efectos de los fármacos
3.
Food Chem Toxicol ; 134 Suppl 2: 110948, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31756354

RESUMEN

The existing information supports the use of this material as described in this safety assessment. 4-(p-Hydroxyphenyl)-2-butanone was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that 4-(p-hydroxyphenyl)-2-butanone is not genotoxic. Data on 4-(p-hydroxyphenyl)-2-butanone provide a calculated MOE >100 for the repeated dose toxicity endpoint. The developmental and reproductive toxicity and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class I material, and the exposure to 4-(p-hydroxyphenyl)-2-butanone is below the TTC (0.03 mg/kg/day and 1.4 mg/day, respectively). Data from 4-(p-hydroxyphenyl)-2-butanone show that there are no safety concerns for skin sensitization under the current declared levels of use. The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; 4-(p-hydroxyphenyl)-2-butanone is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; 4-(p-hydroxyphenyl)-2-butanone was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Asunto(s)
Butanonas/toxicidad , Odorantes , Animales , Butanonas/química , Seguridad de Productos para el Consumidor , Evaluación Preclínica de Medicamentos , Determinación de Punto Final , Humanos , Pruebas de Mutagenicidad , Nivel sin Efectos Adversos Observados , Medición de Riesgo , Salmonella typhimurium/efectos de los fármacos
4.
Food Chem Toxicol ; 134 Suppl 2: 110999, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31783104

RESUMEN

The existing information supports the use of this material as described in this safety assessment. Isobutyl alcohol was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that isobutyl alcohol is not genotoxic. Data on isobutyl alcohol provide a calculated MOE >100 for the repeated dose toxicity and reproductive toxicity endpoints. Data from read-across material isoamyl alcohol (CAS # 123-51-3) show that there are no safety concerns for isobutyl alcohol for skin sensitization under the current declared levels of use. The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; isobutyl alcohol is not expected to be phototoxic/photoallergenic. The local respiratory toxicity endpoint was evaluated using the TTC for a Cramer Class I material and the exposure to isobutyl alcohol is below the TTC (1.4 mg/day). The environmental endpoints were evaluated; isobutyl alcohol was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Asunto(s)
Butanoles/toxicidad , Odorantes , Animales , Butanoles/química , Seguridad de Productos para el Consumidor , Evaluación Preclínica de Medicamentos , Determinación de Punto Final , Humanos , Pruebas de Mutagenicidad , Nivel sin Efectos Adversos Observados , Medición de Riesgo , Salmonella typhimurium/efectos de los fármacos
5.
Food Chem Toxicol ; 134 Suppl 2: 110825, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31542434

RESUMEN

Methyl 2-octynoate was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that methyl 2-octynoate is not genotoxic. Data provided methyl 2-octynoate a NESIL of 110 µg/cm2 for the skin sensitization endpoint. The repeated dose, developmental and reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class II material, and the exposure to methyl 2-octynoate is below the TTC (0.009 mg/kg/day, 0.009 mg/kg/day, and 0.47 mg/day, respectively). The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; methyl 2-octynoate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; methyl 2-octynoate was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Asunto(s)
Caprilatos/toxicidad , Odorantes , Animales , Caprilatos/química , Seguridad de Productos para el Consumidor , Evaluación Preclínica de Medicamentos , Determinación de Punto Final , Humanos , Pruebas de Mutagenicidad , Nivel sin Efectos Adversos Observados , Medición de Riesgo , Salmonella typhimurium/efectos de los fármacos
6.
Food Chem Toxicol ; 134 Suppl 2: 110716, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31365887

RESUMEN

Methyl ionone (mixture of isomers) was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from methyl ionone (mixture of isomers) show that the material is not genotoxic and provided a NESIL of 70,000 µg/cm2 for the skin sensitization endpoint. Data provided a calculated MOE >100 for the repeated dose toxicity and developmental toxicity endpoints, and data from read-across material (E)-ß-ionone (CAS # 79-77-6) provided a calculated MOE >100 for the reproductive toxicity endpoint. For the local respiratory endpoint, a calculated MOE >100 was provided by the read-across material ß-ionone (CAS # 14901-07-6). The phototoxicity/photoallergenicity endpoints were evaluated based on data and UV spectra; the material is not phototoxic/photoallergenic. The environmental endpoints were evaluated with data from the target chemical and read-across material α-allylionone (CAS # 79-78-7), and the material was not found to be PBT; its risk quotients, based on current volume of use in Europe and North America (PEC/PNEC), are <1.


Asunto(s)
Odorantes , Terpenos/toxicidad , Animales , Línea Celular , Seguridad de Productos para el Consumidor , Evaluación Preclínica de Medicamentos , Determinación de Punto Final , Escherichia coli/efectos de los fármacos , Humanos , Isomerismo , Pruebas de Mutagenicidad , Nivel sin Efectos Adversos Observados , Medición de Riesgo , Salmonella typhimurium/efectos de los fármacos , Terpenos/química
7.
Food Chem Toxicol ; 130 Suppl 1: 110607, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31233870

RESUMEN

The existing information supports the use of this material as described in this safety assessment. Isobutyl propionate was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog isobutyl acetate (CAS # 110-19-0) show that isobutyl propionate is not expected to be genotoxic. Data from read-across analog isoamyl acetate (CAS # 123-92-2) show that there are no safety concerns for isobutyl propionate for skin sensitization under the current declared levels of use. The repeated dose and reproductive endpoints were evaluated using the TTC for a Cramer Class I material, and the exposure to isobutyl propionate is below the TTC (0.03 mg/kg/day and 0.03 mg/kg/day, respectively). For the local respiratory endpoint, a calculated MOE >100 was provided by read-across analog butyl acetate (CAS # 123-86-4). The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; isobutyl propionate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; isobutyl propionate is not PBT as per the IFRA Environmental Standards. For the risk assessment, isobutyl propionate was not able to be risk screened as there were no reported volumes of use for North America or Europe in the 2015 IFRA Survey.


Asunto(s)
Perfumes/química , Perfumes/toxicidad , Propionatos/química , Propionatos/toxicidad , Pruebas de Toxicidad/métodos , Animales , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Humanos , Estructura Molecular , Medición de Riesgo
8.
Food Chem Toxicol ; 130 Suppl 1: 110622, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31238136

RESUMEN

The existing information supports the use of this material as described in this safety assessment. Methyl 2-nonenoate was evaluated for genotoxicity, repeated dose toxicity, reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from read-across analog ethyl trans-2,cis-4-decadienoate (CAS # 3025-30-7) show that methyl 2-nonenoate is not expected to be genotoxic. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class I material, and the exposure to methyl 2-nonenoate is below the TTC (0.03 mg/kg/day, 0.03 mg/kg/day, and 1.4 mg/day, respectively). Data from the target and read-across analog isobutyl-2-butenoate (CAS # 589-66-2) do not indicate the material is a sensitizer. The phototoxicity/photoallergenicity endpoints were evaluated based on data and UV spectra; methyl 2-nonenoate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; methyl 2-nonenoate was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.


Asunto(s)
Ácidos Grasos Monoinsaturados/química , Ácidos Grasos Monoinsaturados/toxicidad , Perfumes/química , Perfumes/toxicidad , Pruebas de Toxicidad/métodos , Animales , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Humanos , Estructura Molecular , Medición de Riesgo
9.
Food Chem Toxicol ; 130 Suppl 1: 110588, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31216429

RESUMEN

There are insufficient toxicity data on the target material propanal diethyl acetal (CAS # 4744-08-5). Hence, in silico evaluation was conducted to determine read-across analogs for this material. Based on structural similarity, reactivity, metabolism data, physical-chemical properties, and expert judgment, analogs acetal (CAS # 105-57-7) and butane, 1,1'-[methylenebis(oxy)]bis- (CAS # 2568-90-3) were identified as read-across materials with sufficient data for toxicological evaluation of genotoxicity.


Asunto(s)
Cetonas/química , Perfumes/química , Perfumes/toxicidad , Pruebas de Toxicidad/métodos , Animales , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Humanos , Estructura Molecular , Medición de Riesgo
10.
Anthropol Med ; 26(1): 65-86, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28671478

RESUMEN

The co-existence of different types of medical systems (medical pluralism) is a typical feature of India's healthcare system. For conditions such as influenza-like illness (ILI), where non-specific disease signs/symptoms exist, clinical reasoning in the context of medical pluralism becomes crucial. Recognising this need, we undertook a qualitative study, which explored factors underpinning clinical decisions on diagnosis and management of ILI. The study involved semi-structured interviews including clinical vignettes with 20 healthcare practitioners (working within allopathy, homeopathy and Ayurveda) working in the private healthcare sector in Solapur city, India. An inquiry was conducted into criteria influencing the diagnosis, treatment, referral to specialist care and role of treatment guidelines for ILI. Thematic analysis was used to identify aspects relating to ILI diagnosis, treatment and referral. The diagnosis of influenza was based largely on clinical symptoms suggestive of influenza in the absence of other diagnoses. Referral for laboratory tests was only initiated if illness did not resolve, generally after 2-3 consultations. Antibiotics were often prescribed for persistent illness, with antivirals rarely considered. Some differences between practitioners from different medical systems were observed in relation to treatment and referral in case of persistent illness. A combination of analytical and intuitive clinical reasoning was used by the participants and clinical decisions were based on both social and clinical factors. Clinical decision-making was rarely a linear process and respondents felt that broad guidelines on influenza that allowed doctors to account for the sociocultural context within which they practised medicine would be helpful.


Asunto(s)
Antropología Médica , Toma de Decisiones Clínicas , Gripe Humana/terapia , Medicina Basada en la Evidencia , Humanos , India , Gripe Humana/epidemiología , Investigación Cualitativa
11.
J Environ Qual ; 34(4): 1214-23, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15942040

RESUMEN

Pasture systems in Hawaii are based primarily on kikuyugrass (Pennisetum clandestinum Hochst. ex Chiov.). Relationships among kikuyugrass P concentration, animal P requirements, and various soil P determinations are needed to help identify source areas for implementing pasture management strategies to limit P loss via overland flow. A total of 51 rotationally stocked kikuyugrass pastures (>20 yr old) with contrasting soil chemical properties were sampled. A satisfactory predictive relationship between modified-Truog (MT)-extractable phosphorus (P(MT)) and dissolved (<0.45-mum pore diameter), molybdate-reactive phosphorus (DRP) desorbed from soil in a water extract (DRP(WE)) was found when 0- to 4-cm-depth data for the soil orders with medium to high DRP(WE) (two Mollisols and an Inceptisol) were pooled separately from those with low DRP(WE) (five Andisols, three Ultisols, and an Oxisol). The oxalate phosphorus saturation index (PSI(ox)) procedure was the best predictor of DRP(WE) across soil orders when oxalate-extractable molybdate-reactive phosphorus (RP(ox)) was used to calculate PSI(ox) (PSI(ox)RP) rather than when total oxalate-extractable phosphorus (TP(ox)) was used (PSI(ox)TP). There was little DRP(WE) until PSI(ox)RP exceeded 6% or PSI(ox)TP exceeded 8%. A more empirical dilute-acid phosphorus saturation index (PSI(MT)) was also calculated using P(MT) and MT-extractable iron (Fe(MT)) and aluminum (Al(MT)). The PSI(MT) procedure showed some utility in predicting DRP(WE), was positively related to the PSI(ox) procedures, and can be more readily performed in agronomic soil testing laboratories than PSI(ox). The present research suggests that while Hawaiian kikuyugrass pastures tend to be sufficient to high in forage P, potential soil P release to water only appeared to be a possible environmental concern for the Mollisol and Inceptisol sites.


Asunto(s)
Pennisetum/química , Fósforo/análisis , Animales , Animales Domésticos , Monitoreo del Ambiente , Hawaii , Plantas Comestibles , Suelo
12.
Curr Pharm Des ; 10(9): 1035-44, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15078131

RESUMEN

The enhancement of GABA-mediated synaptic transmission underlies the pharmacotherapy of various neurological diseases. GABAA receptors are thus targets for neuroactive drugs, including classical benzodiazepines, mediating their anxiolytic, hypnotic and anticonvulsant effects via the benzodiazepine site (BZS). Based on findings that low intrinsic efficacy and subtype selectivity can greatly improve the specificity of drugs targeting the BZS, recent research has identified possible drug leads with apparently little side effects. In particular, drug leads of natural sources have been identified as promising candidates. This review describes the advances in the design of effective therapeutics targeting the GABAA receptor, focusing on the more recent research on naturally occurring drug leads. This includes discussion on the isolation of neuroactive alkaloids and flavonoids from herbal medicines and their rational development based on structure-activity relationships studies. Interest in the development of effective therapeutics from natural sources is clear and awaits to be seen whether their medicinal potential can be fulfilled.


Asunto(s)
Benzodiazepinas/farmacología , Preparaciones de Plantas/farmacología , Receptores de GABA-A/efectos de los fármacos , Alcaloides/química , Alcaloides/farmacología , Animales , Benzodiazepinas/química , Diseño de Fármacos , Flavonoides/química , Flavonoides/farmacología , Humanos , Ligandos , Estructura Molecular , Preparaciones de Plantas/química , Receptores de GABA-A/química , Relación Estructura-Actividad
13.
Am J Chin Med ; 29(1): 149-54, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11321472

RESUMEN

Twenty-three ICR mice were force fed orally with American ginseng extract, Panax quinquefolius, (Cold FX) for 4 days. Another 20 mice were fed with water as placebo in a similar fashion. Formalin tests which yield typically two phases of pain behavior were done in both groups. Although there was no difference in the first phase between groups, mice treated with Cold FX spent significantly less time in licking and biting of the injured paws in the second phase. The data indicate that American ginseng may have analgesic effect in this chronic pain model.


Asunto(s)
Analgésicos/farmacología , Panax , Plantas Medicinales , Animales , Formaldehído/efectos adversos , Masculino , Ratones , Ratones Endogámicos ICR , Dimensión del Dolor , Extractos Vegetales
14.
Chem Biol ; 8(1): 33-45, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11182317

RESUMEN

BACKGROUND: Picornaviruses comprise a family of small, non-enveloped RNA viruses. A common feature amongst many picornaviruses is a hydrophobic pocket in the core of VP1, one of the viral capsid proteins. The pocket is normally occupied by a mixture of unidentified, fatty acid-like moieties, which can be competed out by a family of capsid-binding, antiviral compounds. Many members of the Picornaviridae family are pathogenic to both humans and livestock, yet no adequate therapeutics exist despite over a decade's worth of research in the field. To address this challenge, we developed a strategy for rapid identification of capsid-binding anti-picornaviral ligands. The approach we took involved synthesizing structurally biased combinatorial libraries that had been targeted to the VP1 pocket of poliovirus and rhinovirus. The libraries are screened for candidate ligands with a high throughput mass spectrometry assay. RESULTS: Using the mass spectrometry assay, we were able to identify eight compounds from a targeted library of 75 compounds. The antiviral activity of these candidates was assessed by (i) measuring the effect on the kinetics of viral uncoating and (ii) the protective effect of each drug in traditional cell-based assays. All eight of the candidates exhibited antiviral activity, but three of them were particularly effective against poliovirus and rhinovirus. CONCLUSIONS: The results illustrate the utility of combining structure-based design with combinatorial chemistry. The success of our approach suggests that assessment of small, targeted libraries, which query specific chemical properties, may be the best strategy for surveying all of chemical space for ideal anti-picornaviral compounds.


Asunto(s)
Antivirales/síntesis química , Técnicas Químicas Combinatorias/métodos , Diseño de Fármacos , Picornaviridae/efectos de los fármacos , Animales , Antivirales/química , Antivirales/farmacología , Cápside/metabolismo , Efecto Citopatogénico Viral/efectos de los fármacos , Evaluación Preclínica de Medicamentos , Células HeLa , Humanos , Técnicas In Vitro , Picornaviridae/metabolismo , Ensayo de Unión Radioligante , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
15.
J Cardiovasc Pharmacol ; 36(2): 263-9, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10942170

RESUMEN

The effects of purified baicalin and baicalein from the traditional Chinese herb, Huangqin, on contractions induced by phenylephrine, U46619, and high extracellular K+ were investigated in isolated rat mesenteric arteries. Both baicalin (1-100 microM) and baicalein (1-50 microM) potentiated the contractile response to phenylephrine in a concentration-related manner. Both flavonoids (10 microM) also enhanced the U46619- or 40 mM K+-induced contractions. Baicalein (100-300 microM) reduced the phenylephrine-induced tone. Prazosin at 1 microM did not affect U46619-induced contraction in the absence and presence of baicalein or baicalin. Neither baicalin (1-100 microM) nor baicalein (1-100 microM) affected the basal tension. Removal of the functional endothelium abolished the potentiating effects of baicalin and baicalein in arteries preconstricted by both constrictors. Pretreatment of endothelium-intact rings with 100 microM N(G)-nitro-L-arginine also potentiated phenylephrine- or U46619-induced contraction but completely inhibited the effects of baicalin and baicalein. Pretreatment with 1 mM L-arginine reversed the enhancing effect of baicalin but not of baicalein on phenylephrine-evoked contraction. Pretreatment with 10 microM baicalin or 10 microM baicalein significantly reduced the endothelium-dependent relaxation induced by acetylcholine or ionomycin. These results indicate that both baicalin and baicalein potentiated the evoked contractile response, likely through inhibition of nitric oxide formation and/or release in the endothelium.


Asunto(s)
Medicamentos Herbarios Chinos/farmacología , Flavanonas , Flavonoides/farmacología , Arterias Mesentéricas/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/antagonistas & inhibidores , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacología , Acetilcolina/farmacología , Animales , Arginina/farmacología , Sinergismo Farmacológico , Flavonoides/aislamiento & purificación , Técnicas In Vitro , Masculino , Contracción Muscular/efectos de los fármacos , Fenilefrina/antagonistas & inhibidores , Fenilefrina/farmacología , Ratas , Ratas Sprague-Dawley , Vasoconstrictores/antagonistas & inhibidores , Vasoconstrictores/farmacología
16.
Immunopharmacology ; 30(1): 79-87, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7591716

RESUMEN

Radix bupleuri, the root of Bupleuri spp., Chinese medicinal herbs used for the treatment of influenza, malaria and menstrual disorders, were extracted with hot water and separated into five different fractions (RB, RBI, RBII, RBIII and RBIV) by stepwise alcohol precipitation. One of these fractions, RBI, was then fractionated into RBIa and RBIb by gel filtration using G-100 Sephadex. These two fractions were further purified into RBIai, RBIaii and RBIbi, RBIbii fractions respectively by ion-exchange chromatography using DEAE-Sephadex. Each of these fractions is a heteropolymer consisting mainly of carbohydrate and varying proportions of protein and uronic acid. RBIaii was found to show strong anti-tumor activities in sarcoma-bearing mice. Mechanistic studies showed that RBIaii exhibited a potent activating effect on the cytotoxic activity of macrophages, NK and LAK cells against tumor cells. In addition, RBIaii could increase the number of tumor infiltrating lymphocytes (TILs) in the tumor site of WEHI-164-bearing mice. Furthermore, RBIaii could induce the release of interferon-gamma by lymphocytes in vitro.


Asunto(s)
Adyuvantes Inmunológicos/farmacología , Citotoxicidad Inmunológica/efectos de los fármacos , Medicamentos Herbarios Chinos/farmacología , Adyuvantes Inmunológicos/química , Animales , Carbohidratos/análisis , Medicamentos Herbarios Chinos/química , Femenino , Interferón gamma/biosíntesis , Interferón gamma/efectos de los fármacos , Células Asesinas Activadas por Linfocinas/efectos de los fármacos , Células Asesinas Naturales/efectos de los fármacos , Activación de Linfocitos/efectos de los fármacos , Linfocitos Infiltrantes de Tumor/efectos de los fármacos , Activación de Macrófagos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Proteínas/análisis , Sarcoma Experimental/inmunología , Sarcoma Experimental/terapia , Células Tumorales Cultivadas , Ácidos Urónicos/análisis
17.
Cancer Lett ; 45(1): 71-7, 1989 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2713825

RESUMEN

Ingredients of betel quids, which have been linked to the high incidence of precancerous oral lesions and oral cancers, were examined for their promoting activity. Aqueous extracts were tested using the bovine papillomavirus (BPV) DNA transformation assay, which consists of cultured C3H/10T1/2 cells transfected with the plasmid pdPBV-1 as targets, and the frequency of transformed foci as endpoints. Areca nut extracts enhanced the formation of BPV DNA-induced transformed foci approximately tenfold. No promoting activity was detected in two samples of chewing tobacco examined. The addition of retinol to the areca nut extract inhibited its tumour promoting effect in a dose-dependent manner, completely abolishing the promoting activity at a dose of 10(-6) M. The experimental results are compared with epidemiological data on oral cancer incidences among chewers of different areca nut/tobacco mixtures and with the chemopreventive effect of vitamin A administered to betel quid chewers.


Asunto(s)
Areca , Carcinógenos , Transformación Celular Neoplásica , Aberraciones Cromosómicas , Extractos Vegetales/farmacología , Plantas Medicinales , Vitamina A/farmacología , Animales , Transformación Celular Neoplásica/efectos de los fármacos , Células Cultivadas , Células Clonales , Ratones , Ratones Endogámicos C3H , Plantas Tóxicas , Plásmidos , Nicotiana , Transfección
18.
Proc Natl Acad Sci U S A ; 81(22): 7026-30, 1984 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-6594678

RESUMEN

In the presence of ATP, recA protein forms a presynaptic complex with single-stranded DNA that is an obligatory intermediate in homologous pairing. Presynaptic complexes of recA protein and circular single strands that are active in forming joint molecules can be isolated by gel filtration. These isolated active complexes are nucleoprotein filaments with the following characteristics: (i) a contour length that is at least 1.5 times that of the corresponding duplex DNA molecule, (ii) an ordered structure visualized by negative staining as a striated filament with a repeat distance of 9.0 nm and a width of 9.3 nm, (iii) approximately 8 molecules of recA protein and 20 nucleotide residues per striation. The widened spacing between bases in the nucleoprotein filament means that the initial matching of complementary sequences must involve intertwining of the filament and duplex DNA, unwinding of the latter, or some combination of both to equalize the spacing between nascent base pairs. These experiments support the concept that recA protein first forms a filament with single-stranded DNA, which in turn binds to duplex DNA to mediate both homologous pairing and subsequent strand exchange.


Asunto(s)
ADN de Cadena Simple/genética , Rec A Recombinasas/genética , Recombinación Genética , Adenosina Trifosfato , Proteínas de Unión al ADN , Desoxirribonucleoproteínas , Sustancias Macromoleculares , Microscopía Electrónica
19.
Mutat Res ; 64(3): 167-82, 1979 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-470967

RESUMEN

A simple technique for the detection of DNA-modifying agents is described. The double-stranded covalently closed circular DNA of phage PM2 is exposed to the modifying agent and then analysed for DNA damages by assays involving only incubation steps and filtration through nitrocellulose filters. The technique described allows the measurement of DNA modifications which lead to local denaturation of the DNA double helix, interstrand cross-links, single- and double-strand breaks, damages which render the phosphodiester bonds of the DNA sensitive to hydrolysis and damages which labilise the glycosylic bond between base and sugar moiety.


Asunto(s)
Evaluación Preclínica de Medicamentos/métodos , Mutágenos , ADN Circular/análisis , ADN Viral/análisis , Filtros Microporos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA