Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Nature ; 568(7751): 221-225, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30944480

RESUMEN

The global land and ocean carbon sinks have increased proportionally with increasing carbon dioxide emissions during the past decades1. It is thought that Northern Hemisphere lands make a dominant contribution to the global land carbon sink2-7; however, the long-term trend of the northern land sink remains uncertain. Here, using measurements of the interhemispheric gradient of atmospheric carbon dioxide from 1958 to 2016, we show that the northern land sink remained stable between the 1960s and the late 1980s, then increased by 0.5 ± 0.4 petagrams of carbon per year during the 1990s and by 0.6 ± 0.5 petagrams of carbon per year during the 2000s. The increase of the northern land sink in the 1990s accounts for 65% of the increase in the global land carbon flux during that period. The subsequent increase in the 2000s is larger than the increase in the global land carbon flux, suggesting a coincident decrease of carbon uptake in the Southern Hemisphere. Comparison of our findings with the simulations of an ensemble of terrestrial carbon models5,8 over the same period suggests that the decadal change in the northern land sink between the 1960s and the 1990s can be explained by a combination of increasing concentrations of atmospheric carbon dioxide, climate variability and changes in land cover. However, the increase during the 2000s is underestimated by all models, which suggests the need for improved consideration of changes in drivers such as nitrogen deposition, diffuse light and land-use change. Overall, our findings underscore the importance of Northern Hemispheric land as a carbon sink.


Asunto(s)
Dióxido de Carbono/análisis , Dióxido de Carbono/historia , Secuestro de Carbono , Mapeo Geográfico , Sedimentos Geológicos/química , Atmósfera/química , Carbono/química , Dióxido de Carbono/química , China , Materiales de Construcción/análisis , Bosques , Combustibles Fósiles/análisis , Historia del Siglo XX , Historia del Siglo XXI , Modelos Lineales , Modelos Teóricos , Nitrógeno/química , Siberia , Incertidumbre
2.
J Microsc ; 253(3): 204-18, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24467513

RESUMEN

BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorophores are widely used in bioimaging to label proteins, lipids and nucleotides, but in spite of their attractive optical properties they tend to be prone to self-quenching because of their notably small Stokes shift. Herein, we compare two BODIPY compounds from a recently developed family of naphthyridine substituted BODIPY derivatives, one a visible emitting derivative (BODIPY-VIS) and one a near-infrared emitting fluorophore with a Stokes shift of approximately 165 nm as contrast reagents for live mammalian cells and murine brain tissue. The compounds were rendered water soluble by their conjugation to polyethylene glycol (PEG). Both PEGylated compounds exhibited good cell uptake compared with their parent compounds and confocal fluorescence microscopy revealed all dyes explored to be nuclear excluding, localizing predominantly within the lipophilic organelles; the endoplasmic reticulum and mitochondria. Cytotoxicity studies revealed that these BODIPY derivatives are modestly cytotoxic at concentrations exceeding 10 µM where they induce apoptosis and necrosis. Although the quantum yield of emission of the visible emitting fluorophore was over an order of magnitude greater than the Mega-Stokes shifted probe, the latter showed considerably reduced tendency to self quench and less interference from autofluorescence. The near-infrared probe also showed good penetrability and staining in live tissue samples. In the latter case similar tendency to exclude the nucleus and to localize in the mitochondria and endoplasmic reticulum was observed as in live cells. This to our knowledge is the first demonstration of such a Mega-Stokes BODIPY probe applied to cell and tissue imaging.


Asunto(s)
Compuestos de Boro/química , Colorantes Fluorescentes/química , Histocitoquímica/métodos , Microscopía Fluorescente/métodos , Animales , Apoptosis/efectos de los fármacos , Compuestos de Boro/farmacocinética , Compuestos de Boro/farmacología , Química Encefálica , Células CHO , Línea Celular , Supervivencia Celular/efectos de los fármacos , Cricetinae , Cricetulus , Femenino , Colorantes Fluorescentes/farmacocinética , Colorantes Fluorescentes/farmacología , Células HeLa , Humanos , Ratones , Agua
3.
J Laryngol Otol ; 136(7): 628-631, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34698004

RESUMEN

OBJECTIVE: This study aimed to investigate whether children with cochlear implants received the recommended vaccinations according to New Zealand national immunisation guidelines and to report the incidence of meningitis in this population after intervention. METHOD: A retrospective review of the vaccination coverage of paediatric patients receiving cochlear implants between 2005 and 2019 was performed. RESULTS: Data were collected on 203 children. Evidence of immunisation against Haemophilus influenza B was documented in 94.1 per cent of this cohort and 21.2 per cent received the seasonal influenza vaccine. The pneumococcal conjugate vaccine was fully administered in 81.8 per cent of children; however, only 16.9 per cent of eligible children had received the pneumococcal polysaccharide vaccine. There was marked improvement in compliance to the pneumococcal conjugate vaccine once it became fully funded for cochlear implant patients. CONCLUSION: Despite established guidelines, the paediatric vaccination rates were less than expected. Work is in progress to address this.


Asunto(s)
Implantación Coclear , Implantes Cocleares , Niño , Humanos , Vacunas Neumococicas/uso terapéutico , Vacunación , Vacunas Conjugadas/uso terapéutico
4.
Nat Med ; 1(3): 260-6, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7585044

RESUMEN

For the discovery of new cancer chemopreventive agents, we have studied the potential of plant extracts to inhibit phorbol ester-induced ornithine decarboxylase (ODC) activity in cell culture. Four active rotenoids were obtained from the African plant Mundulea sericea (Leguminosae). These isolates were highly potent when evaluated for inhibition of chemically induced preneoplastic lesions in mammary organ culture and inhibition of papillomas in the two-stage mouse skin model, and they appear to function by a unique mechanism at the level of ODC messenger RNA expression. Based on our findings, rotenoids can be regarded as promising new chemopreventive or anticancer agents.


Asunto(s)
Antineoplásicos Fitogénicos/farmacología , Neoplasias Experimentales/prevención & control , Ornitina Descarboxilasa/genética , Rotenona/análogos & derivados , Rotenona/farmacología , 9,10-Dimetil-1,2-benzantraceno , Animales , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Femenino , Regulación Enzimológica de la Expresión Génica , Células HL-60/citología , Humanos , Ratones , Ratones Endogámicos BALB C , Neoplasias Experimentales/enzimología , Neoplasias Experimentales/patología , Técnicas de Cultivo de Órganos , Lesiones Precancerosas/prevención & control , Proteína Quinasa C/metabolismo , ARN Mensajero/genética , Neoplasias Cutáneas/inducido químicamente , Acetato de Tetradecanoilforbol/antagonistas & inhibidores
5.
Int J Obstet Anesth ; 34: 108-112, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-29544721

RESUMEN

Congenital muscular dystrophies are characterised by progressive skeletal muscle weakness from birth or early infancy. Maternal respiratory compromise, joint contractures and presence of spinal instrumentation or fusion are some of the anaesthetic challenges that may be encountered in the obstetric setting. The choice of anaesthetic technique for surgical delivery needs to be considered on an individual basis. Multidisciplinary involvement is paramount to optimise peripartum care and outcomes. In this case report, we present the use of dexmedetomidine, humidified high-flow nasal oxygen, rocuronium and sugammadex in the anaesthetic management of a wheelchair-bound, non-invasive bilevel positive airway pressure ventilation-dependent parturient with congenital muscular dystrophy, who was presenting for caesarean section.


Asunto(s)
Androstanoles/antagonistas & inhibidores , Anestesia Epidural/métodos , Anestesia Obstétrica/métodos , Cesárea/métodos , Dexmedetomidina , Hipnóticos y Sedantes , Distrofias Musculares/complicaciones , Fármacos Neuromusculares no Despolarizantes/antagonistas & inhibidores , Terapia por Inhalación de Oxígeno/métodos , gamma-Ciclodextrinas , Adulto , Manejo de la Vía Aérea , Servicios Médicos de Urgencia , Femenino , Humanos , Recién Nacido , Embarazo , Complicaciones del Embarazo , Resultado del Embarazo , Rocuronio , Sugammadex
6.
J Natl Cancer Inst ; 89(3): 212-8, 1997 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-9017001

RESUMEN

BACKGROUND: The form of vitamin D (vitamin D3) in fortified milk and the provitamin D produced by the body undergo metabolic activation to a biologically active form, 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3]. This compound can induce cell differentiation and can prevent proliferation of cancer cells. However, because 1alpha,25(OH)2D3 is hypercalcemic (effective in increasing serum calcium level), it is not suitable for use in cancer prevention or cancer therapy trials. PURPOSE: We synthesized a vitamin D5 series analogue, 1alpha-hydroxy, 24-ethyl-cholecalciferol, or 1alpha-hydroxyvitamin D5 [1alpha(OH)D5], and evaluated its chemopreventive activity in carcinogen-treated mammary glands in organ culture experiments. METHODS: The analogue 1alpha(OH)D5 was synthesized from sitosterol acetate and was characterized by nuclear magnetic resonance. Its purity was evaluated by high-pressure liquid chromatography. The calcemic activities of vitamin D3 and D5 analogues were determined in vitamin D-deficient Sprague-Dawley rats. Mammary glands of BALB/c mice were placed in organ culture and treated with the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) to induce preneoplastic lesions. Vitamin D analogues were added to the culture medium at four different concentrations, and formation of mammary lesions was evaluated. The effects of 1alpha(OH)D5 and 1alpha,25(OH)2D3 on the expression of vitamin D receptors (VDRs) and transforming growth factor-beta1 (TGF-beta1) were studied by immunohistochemistry. Statistical significance was determined by the chi-squared test. All reported P values were two-sided. RESULTS: 1alpha,25(OH)2D3 was fourfold more calcemic than 1alpha(OH)D5 at a dose of 0.042 microg/kg per day in rats. Both 1alpha,25(OH)2D3 and 1alpha(OH)D5 inhibited the development of DMBA-induced preneoplastic lesions in mouse mammary glands compared with untreated glands. The effect of the vitamin D3 analogue was observed at a much lower concentration (0.01 microM). Treatment with 1alpha(OH)D5 resulted in a dose-related (0.01-10.0 microM) inhibition without any toxicity, whereas the vitamin D3 analogue was highly potent but toxic at concentrations of 1.0 microM or higher. Normal mouse mammary glands poorly express VDR and TGF-beta1; incubation with 1alpha(OH)D5 or 1alpha,25(OH)2D3 dramatically induced their expression. CONCLUSIONS: This is the first report showing the possibility of chemoprevention by a vitamin D5 series compound. We conclude that 1alpha(OH)D5 is less calcemic than 1alpha,25(OH)2D3. It is nontoxic at a wide range of concentrations, but it is potent in inhibiting the development of preneoplastic lesions in mammary glands in organ culture. In addition, we show for the first time the induction of TGF-beta1 in normal mammary tissues by a chemopreventive agent. IMPLICATIONS: 1alpha(OH)D5 is a good candidate for in vivo chemoprevention studies. It may mediate its action by inducing expression of VDR and of TGF-beta1, as is seen in other systems.


Asunto(s)
Calcitriol/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Hidroxicolecalciferoles/farmacología , Neoplasias Mamarias Experimentales/química , Neoplasias Mamarias Experimentales/prevención & control , Receptores de Calcitriol/efectos de los fármacos , Factor de Crecimiento Transformador beta/efectos de los fármacos , Vitamina D/análogos & derivados , 9,10-Dimetil-1,2-benzantraceno , Animales , Calcio/sangre , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Neoplasias Mamarias Experimentales/inducido químicamente , Ratones , Ratones Endogámicos BALB C , Técnicas de Cultivo de Órganos , Ratas , Ratas Sprague-Dawley , Receptores de Calcitriol/biosíntesis , Receptores de Calcitriol/genética , Factor de Crecimiento Transformador beta/biosíntesis , Factor de Crecimiento Transformador beta/genética
7.
J Natl Cancer Inst ; 92(22): 1836-40, 2000 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-11078761

RESUMEN

BACKGROUND: Although the active form of vitamin D, i.e., 1,25-dihydroxyvitamin D(3), is a potent cell-differentiating agent, its use in cancer prevention or therapy is precluded because it induces excessive blood calcium levels (hypercalcemia). However, less calcemic or noncalcemic synthetic analogues of vitamin D(3) are poorly effective against mammary carcinogenesis. We synthesized an analogue of vitamin D(5), 1alpha-hydroxy-24-ethylcholecalciferol (1alpha-hydroxyvitamin D(5)), which was less calcemic than 1,25-dihydroxyvitamin D(3) and prevented the development of precancerous lesions in mammary glands. Here, we evaluate its efficacy in an experimental rat mammary carcinogenesis model. METHODS: Sprague-Dawley rats were treated with 1alpha-hydroxyvitamin D(5) beginning 2 weeks before carcinogen treatment. Animals received an intravenous injection of N-methyl-N-nitrosourea at 80 days of age and continued to receive dietary 1alpha-hydroxyvitamin D(5) for an additional 105 days. Tumor incidence and multiplicity were determined, and plasma concentrations of calcium and phosphorus were measured. The efficacy of 1alpha-hydroxyvitamin D(5) at different stages of carcinogenesis was determined in mouse mammary gland organ culture. All statistical tests were two-sided. RESULTS: The tumor incidence was reduced from 80% (95% confidence interval [CI] = 51.9%-95.7%) in control rats to 53.3% (95% CI = 26.6%-78.8%) and 46.6% (95% CI = 21.3%-73.4%) in rats treated with 1alpha-hydroxyvitamin D(5) at 25 microg/kg diet and 50 microg/kg diet, respectively. The tumor multiplicity was reduced from 1.6 tumors per rat to 1.2 (95% CI for the difference = -0.45 to 1.25; P=.34) and 0.8 (95% CI for the difference = 0.14-1.46; P =.02), respectively. There was no statistically significant increase in the plasma calcium or phosphorus concentration at either dose level. The vitamin D(5) analogue was effective during both the initiation and the promotion stages of mammary lesion formation in organ culture. CONCLUSION: Our findings indicate that 1alpha-hydroxyvitamin D(5) reduces the incidence of mammary carcinogenesis in vivo. This analogue appears to be a good candidate for further development as a chemopreventive agent.


Asunto(s)
Anticarcinógenos/farmacología , Hidroxicolecalciferoles/farmacología , Neoplasias Mamarias Experimentales/prevención & control , Animales , Anticarcinógenos/administración & dosificación , Anticarcinógenos/efectos adversos , Calcio/sangre , Carcinógenos , Intervalos de Confianza , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Hidroxicolecalciferoles/administración & dosificación , Hidroxicolecalciferoles/efectos adversos , Incidencia , Neoplasias Mamarias Experimentales/sangre , Neoplasias Mamarias Experimentales/inducido químicamente , Metilnitrosourea , Fósforo/sangre , Ratas , Ratas Sprague-Dawley
8.
Cancer Res ; 57(2): 272-8, 1997 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-9000567

RESUMEN

Chemoprevention involves the use of natural or synthetic substances to reduce the risk of developing cancer. Two dietary components capable of mediating chemopreventive activity in animal models by modulation of drug-metabolizing enzymes are sulforaphane, an aliphatic isothiocyanate, and brassinin, an indole-based dithiocarbamate, both found in cruciferous vegetables. We currently report the synthesis and activity of a novel cancer chemopreventive agent, (+/-)-4-methylsulfinyl-1-(S-methyldithiocarbamyl)-butane (trivial name, sulforamate), an aliphatic analogue of brassinin with structural similarities to sulforaphane. This compound was shown to be a monofunctional inducer of NAD(P)H:quinone oxidoreductase [quinone reductase (QR)], a Phase II enzyme, in murine Hepa 1c1c7 cell culture and two mutants thereof. Induction potential was comparable to that observed with sulforaphane (concentration required to double the specific activity of QR, approximately 0.2 microM), but cytotoxicity was reduced by about 3-fold (IC50 approximately 30 microm). In addition, sulforaphane, as well as the analogue, increased glutathione levels about 2-fold in cultured Hepa 1c1c7 cells. Induction of QR was regulated at the transcriptional level. Using Northern blotting techniques, time- and dose-dependent induction of QR mRNA levels were demonstrated in Hepa 1c1c7 cell culture. To further investigate the mechanism of induction, HepG2 human hepatoma cells were transiently transfected with QR-chloramphenicol acetyltransferase plasmid constructs containing various portions of the 5'-region of the QR gene. Sulforaphane and the analogue significantly induced (P < 0.0001) CAT activity at a concentration of 12.5 microM by interaction with the antioxidant responsive element (5-14-fold induction) without interacting with the xenobiotic responsive element. Moreover, both compounds significantly induced mouse mammary QR and glutathione S-transferase activity (feeding of 3 mg/mouse intragastric for 4 days), whereas the elevation of hepatic enzyme activities was less pronounced. Both sulforaphane and the analogue were identified as potent inhibitors of preneoplastic lesion formation in carcinogen-treated mouse mammary glands in organ culture (84 and 78% inhibition at 1 microm, respectively). On the basis of these results, the sulforaphane analogue can be regarded as a readily available promising new cancer chemopreventive agent.


Asunto(s)
Anticarcinógenos/uso terapéutico , Glutatión/biosíntesis , Neoplasias Mamarias Experimentales/prevención & control , NAD(P)H Deshidrogenasa (Quinona)/biosíntesis , ARN Mensajero/biosíntesis , Tiocarbamatos/uso terapéutico , Tiocianatos/uso terapéutico , Animales , Anticarcinógenos/síntesis química , Cloranfenicol O-Acetiltransferasa/biosíntesis , Cloranfenicol O-Acetiltransferasa/genética , Inducción Enzimática , Femenino , Genes Reguladores , Humanos , Isotiocianatos , Hígado/enzimología , Neoplasias Mamarias Experimentales/inducido químicamente , Ratones , Ratones Endogámicos BALB C , NAD(P)H Deshidrogenasa (Quinona)/genética , Técnicas de Cultivo de Órganos , Sulfóxidos , Tiocarbamatos/síntesis química , Tiocianatos/síntesis química , Transfección , Células Tumorales Cultivadas
9.
Cancer Res ; 57(16): 3424-8, 1997 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-9270008

RESUMEN

Deguelin, a natural product isolated from Mundulea sericea (Leguminosae), was shown previously to mediate strong inhibition of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity in cell culture and to reduce the formation of preneoplastic lesions when mouse mammary glands were exposed to 7,12-dimethylbenz(a)anthracene. As reported currently, deguelin was synthesized and evaluated for chemopreventive activity in the two-stage 7,12-dimethylbenz(a)anthracene/TPA skin carcinogenesis model with CD-1 mice and in the N-methylnitrosourea mammary carcinogenesis model with Sprague Dawley rats. In the mouse skin study, deguelin reduced tumor incidence from 60% in the control group to 10% in the group treated with a dose of 33 microg, and multiplicity was reduced from 4.2 in the control group to 0.1 in the treatment group. When the dose was increased 10-fold to 330 microg, no tumors were observed in the treatment group. These results correlated with the potential of deguelin to inhibit TPA-induced mouse epidermal ODC activity. When applied topically as a single dose in a time range of 2 h before to 2 h after TPA treatment, deguelin (384 microg) reduced ODC induction by TPA (6.17 microg) by more than 85%. Time course studies indicated that deguelin (33 microg) inhibited TPA (1.17 microg)-induced ODC activity by 70% without affecting the kinetics of induction over a period of 10 h. Complete inhibition of ODC induction was observed at a dose of 330 microg of deguelin. In the rat mammary tumorigenesis study, intragastric administration of 2 or 4 mg of deguelin/kg of body weight daily, 5 days/week, reduced tumor multiplicity from 6.8 tumors/rat in the control group to 5.1 or 3.2 tumors/animal, respectively. At the 4 mg of deguelin/kg of body weight dose level, the tumor latency period was significantly increased. Tumor incidence, however, was unaffected. These data indicate that deguelin exhibits cancer chemopreventive effects in skin and mammary tumorigenesis models and that additional studies are warranted to characterize the cancer chemopreventive or chemotherapeutic potential of this substance more fully.


Asunto(s)
Anticarcinógenos/uso terapéutico , Antineoplásicos Fitogénicos/uso terapéutico , Neoplasias Mamarias Experimentales/prevención & control , Inhibidores de la Ornitina Descarboxilasa , Neoplasias Cutáneas/prevención & control , 9,10-Dimetil-1,2-benzantraceno , Animales , Carcinógenos , Ensayos de Selección de Medicamentos Antitumorales , Inducción Enzimática , Femenino , Neoplasias Mamarias Experimentales/inducido químicamente , Metilnitrosourea , Ratones , Neoplasias Experimentales/inducido químicamente , Neoplasias Experimentales/prevención & control , Ratas , Ratas Sprague-Dawley , Neoplasias Cutáneas/inducido químicamente
10.
Cancer Res ; 57(16): 3429-35, 1997 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-9270009

RESUMEN

Deguelin, a plant-derived rotenoid, mediates potent chemopreventive responses through transcriptional regulation of phorbol ester-induced ornithine decarboxylase (ODC) activity. To explore the mechanism of this effect, the activity of this compound was evaluated with a number of model systems. Using cultured mouse epidermal 308 cells, the steady-state levels of both 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ODC mRNA and c-fos were decreased by treatment with deguelin. ODC activity was also inhibited by bullatacin and various antimitotic agents (podophyllotoxin, vinblastine, and colchicine), but only deguelin and bullatacin were active as inhibitors of ODC levels in a TPA-independent c-Myc-mediated induction system using cultured BALB/c c-MycER cells. These results suggest that antimicrotubule effects, as mediated by rotenone, for example, are not responsible for inhibitory activity facilitated by deguelin. This was confirmed by use of an in vitro model of tubulin polymerization in which deguelin and a variety of other rotenoids were investigated and found to be inactive. As anticipated, however, NADH dehydrogenase was inhibited by these rotenoids. Moreover, inhibition of this enzyme correlated with a rapid depletion of ATP levels and potential to inhibit either TPA- or c-Myc-induced ODC activity. It therefore seems that deguelin-mediated interference with transient requirements for elevated energy can inhibit the induction of ODC activity and thereby yield a cancer chemopreventive response.


Asunto(s)
Anticarcinógenos/farmacología , Antineoplásicos Fitogénicos/farmacología , Inhibidores de la Ornitina Descarboxilasa , Células 3T3 , Adenosina Trifosfato/metabolismo , Animales , Carcinógenos/farmacología , Células Cultivadas , Inducción Enzimática/efectos de los fármacos , Ratones , NADH Deshidrogenasa/antagonistas & inhibidores , Ornitina Descarboxilasa/metabolismo , Polímeros , Proteínas Proto-Oncogénicas c-fos/genética , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Proto-Oncogénicas c-myc/metabolismo , ARN Mensajero/metabolismo , Acetato de Tetradecanoilforbol/farmacología , Tubulina (Proteína)/efectos de los fármacos , Tubulina (Proteína)/metabolismo
11.
Cancer Res ; 59(3): 578-85, 1999 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-9973203

RESUMEN

Induction of phase II enzymes is an important mechanism of chemoprevention. In our search for novel cancer chemopreventive agents, 4'-bromoflavone (4'BF) was found to significantly induce quinone reductase (QR) activity in cultured murine hepatoma 1c1c7 cells (concentration to double activity: 10 nM) and effectively induce the alpha- and mu-isoforms of glutathione S-transferase in cultured H4IIE rat hepatoma cells with no observed toxicity. In short-term dietary studies, 4'BF was also shown to increase QR activity and glutathione levels in rat liver, mammary gland, colon, stomach, and lung in a dose-dependent manner. Induction mediated by 4'BF was bifunctional (induction of both phase I and phase II enzymes) and regulated at the transcriptional level, as revealed by transient transfection studies with plasmid constructs (pDTD-1097CAT, XRE-CAT, and ARE-CAT) and reverse transcription-PCR-based analysis of QR mRNA. In studies conducted with female Sprague Dawley rats, the effects of 4'BF on the relative induction levels of phase I and phase II enzyme activities were investigated in liver and mammary gland. Treatment with 4'BF and 7,12-dimethylbenz[a]anthracene (DMBA) or 4'BF alone did not significantly alter DMBA-induced cytochrome P4501A1 activity (phase I enzyme), but it significantly increased QR activity (phase II enzyme), compared with the DMBA treatment group. In addition, 4'BF was found to be a potent inhibitor of cytochrome P4501A1-mediated ethoxyresorufin-O-deethylase activity, with an IC50 of 0.86 microM. Furthermore, in studies conducted with cultured HepG2 or MCF-7 cells, 4'BF significantly reduced the covalent binding of metabolically activated benzo[a]pyrene to cellular DNA. On the basis of these results, a full-term cancer chemoprevention study was conducted with DMBA-treated female Sprague Dawley rats. Dietary administration of 4'BF (2000 and 4000 mg per kg of diet, from 1 week before to 1 week after DMBA) significantly inhibited the incidence and multiplicity of mammary tumors and greatly increased tumor latency. In summary, 4'BF can be viewed as a relatively simple, readily available, inexpensive compound that is a highly effective cancer chemopreventive agent. The full mechanism of action remains to be defined, but enhancement of detoxification pathways appears to be important.


Asunto(s)
Anticarcinógenos/farmacología , Citocromo P-450 CYP1A1/biosíntesis , Flavonoides/farmacología , Paclitaxel/análogos & derivados , Taxoides , Animales , Anticarcinógenos/síntesis química , Carcinógenos , Inducción Enzimática , Femenino , Flavonoides/síntesis química , Humanos , Inactivación Metabólica , Neoplasias Hepáticas Experimentales/enzimología , Neoplasias Hepáticas Experimentales/prevención & control , Macrólidos , Neoplasias Mamarias Experimentales/inducido químicamente , Neoplasias Mamarias Experimentales/enzimología , Neoplasias Mamarias Experimentales/prevención & control , Ratones , Paclitaxel/farmacología , Ratas , Ratas Sprague-Dawley , Células Tumorales Cultivadas
12.
J Thromb Haemost ; 14(4): 797-806, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26669970

RESUMEN

BACKGROUND: The discovery of pathogen-recognition receptors such as Toll-like receptors on platelets has led to the emergence of the concept of platelets as important components of the host response to infection. Escherichia coli (E. coli)-mediated sepsis is a serious illness characterized by the occurrence of thrombocytopenia. Whereas there has been a wealth of research on platelet activation by Gram-positive bacteria, little is known about the mechanisms associated with Gram-negative bacteria-induced platelet activation with Gram-negative bacteria. OBJECTIVES: To determine the mechanisms by which Gram-negative E. coli induces platelet aggregation. METHODS: Induction of platelet aggregation with E. coli strain O157:H7 was tested in platelet-rich plasma (PRP), washed platelets, and serum depleted of complement factors. Platelet inhibitors (against αII b ß3 , glycoprotein Ibα and FcγRIIa) were used. Platelet thromboxane synthesis was analyzed after E. coli stimulation. Cell binding assays were used to assess the ability of E. coli to support platelet adhesion. Trypsinization was used to determine the role of E. coli surface proteins. RESULTS AND CONCLUSION: E. coli-induced aggregation in PRP was donor-dependent. E. coli O157:H7 induced aggregation with a lag time of 6.9 ± 1.3 min in an αII b ß3 -dependent and FcγRIIa-dependent manner. Furthermore, this interaction was enhanced by the presence of complement, and was dependent on thromboxane synthesis. These results show E. coli to be a potent inducer of platelet aggregation.


Asunto(s)
Escherichia coli O157/patogenicidad , Agregación Plaquetaria , Receptores de IgG/química , Trombocitopenia/inmunología , Plaquetas/inmunología , Membrana Celular/microbiología , Infecciones por Escherichia coli/sangre , Humanos , Activación Plaquetaria , Adhesividad Plaquetaria , Inhibidores de Agregación Plaquetaria/química , Pruebas de Función Plaquetaria , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/inmunología , Plasma Rico en Plaquetas/metabolismo , Sepsis/fisiopatología , Tromboxano B2/química
13.
Diabetes ; 33(5): 470-6, 1984 May.
Artículo en Inglés | MEDLINE | ID: mdl-6202576

RESUMEN

This investigation was designed to determine whether the aldose reductase inhibitor Sorbinil prevented the development of or reversed defects of nerve conduction and axonal transport in streptozotocin-diabetic rats. Untreated diabetes of either 3 or 6 wk duration caused a fall in sciatic motor nerve conduction velocity (MNCV) of 6-9 m/s (P less than 0.001) and significantly reduced the accumulation of axonally transported choline acetyltransferase activity against a 24-h sciatic nerve crush. These functional defects were associated with accumulation of sorbitol and depletion of myo-inositol in the sciatic nerve. Treatment with Sorbinil (25 mg/kg/day, p.o.) throughout the period of diabetes prevented the development of all these abnormalities in both 3- and 6-wk diabetic groups. In a second study, three groups of rats were subject to 3 wk untreated diabetes followed by Sorbinil treatment (as above) for 1, 2, or 3 wk to determine whether the abnormalities expected from 3 wk of untreated diabetes could be reversed. One week of treatment significantly elevated both MNCV and choline acetyltransferase accumulation (P less than 0.05). The longer treatments progressively ameliorated these defects such that the group that received Sorbinil for the second 3 wk of a 6-wk diabetic period gave values that were similar to controls and to diabetic rats that had been given Sorbinil throughout their diabetes. Sorbitol accumulation was markedly reduced by only 1 wk of Sorbinil treatment, but the normalization of myo-inositol levels required 2 wk of treatment. These findings indicate that Sorbinil treatment in diabetic rats prevented and reversed both Sorbitol accumulation and depletion of nerve myo-inositol in the sciatic nerve.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Transporte Axonal , Diabetes Mellitus Experimental/fisiopatología , Neuropatías Diabéticas/tratamiento farmacológico , Imidazoles/uso terapéutico , Imidazolidinas , Conducción Nerviosa , Aldehído Reductasa/antagonistas & inhibidores , Animales , Colina O-Acetiltransferasa/metabolismo , Neuropatías Diabéticas/fisiopatología , Neuropatías Diabéticas/prevención & control , Inositol/metabolismo , Masculino , Ratas , Ratas Endogámicas , Nervio Ciático/fisiopatología , Sorbitol/metabolismo
14.
Eur J Cancer ; 36(6): 780-6, 2000 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10762752

RESUMEN

The role of the active metabolite of vitamin D, 1,25 dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), in cell differentiation is well established. However, its use as a differentiating agent in a clinical setting is precluded due to its hypercalcaemic activity. Recently, we synthesised a relatively non-calcaemic analogue of vitamin D(5), 1alpha-hydroxyvitamin D(5) (1alpha(OH)D(5)), which inhibited the development of carcinogen-induced mammary lesions in culture and suppressed the incidence of chemically induced mammary carcinogmas in rats. In the present study, we determined the differentiating effects of 1alpha-(OH)D(5) in T47D human breast cancer cells and compared its effects with 1,25(OH)(2)D(3). Cells incubated with either 10 or 100 nM of the analogues inhibited cell proliferation in a dose-dependent manner, as measured by the dimethylthiazolyl-2,5-diphenyltetrazolium bromide (MTT) assay. Similar growth-inhibitory effects were also observed for MCF10(neo) cells. Both vitamin D analogues induced cell differentiation, as determined by induction of casein expression and lipid production. However, MCF10(neo) cells failed to respond to either vitamin D analogue and did not undergo cell differentiation. Since the cell differentiating effect of vitamin D is considered to be mediated via the vitamin D receptor (VDR), we examined the induction of VDR using reverse transcriptase-polymerase chain reaction (RT-PCR) in both cells. The results showed that, in T47D cells, both 1,25(OH)(2)D(3) and 1alpha(OH)D(5) induced VDR in a dose-dependent manner. Moreover, both analogues of vitamin D upregulated the expression of vitamin D response element-chloramphenicol acetyl transferase (VDRE-CAT). These results collectively indicate that 1alpha-(OH)D(5) may mediate its cell-differentiating action via VDR in a manner similar to that of 1,25(OH)(2)D(3).


Asunto(s)
Neoplasias de la Mama/patología , Hidroxicolecalciferoles/farmacología , Receptores de Calcitriol/metabolismo , Calcitriol/farmacología , Diferenciación Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Femenino , Expresión Génica , Humanos , Hidroxicolecalciferoles/metabolismo , ARN Mensajero/genética , Receptores de Calcitriol/genética , Elementos de Respuesta , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Activación Transcripcional/efectos de los fármacos , Células Tumorales Cultivadas/efectos de los fármacos
15.
J Med Chem ; 41(4): 468-77, 1998 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-9484497

RESUMEN

Three phencyclidine (PCP) analogues possessing a highly rigid carbocyclic structure and an attached piperidine ring which is free to rotate were synthesized. Each analogue has a specific fixed orientation of the ammonium center of the piperidinium ring to the centrum of the phenyl ring. The binding affinities of the rigid analogues 1-piperidino-7,8-benzobicyclo[4.2.0]octene (14), 1-piperidinobenzobicyclo[2.2.1]heptene (16), and 1-piperidinobenzobicyclo[2.2.2]octene (13) for the PCP receptor ([3H]TCP) and th-receptor (NANM) were determined. The three analogues show low to no affinity for the PCP receptor but good affinity for the th-receptor and can be considered th-receptor selective ligands with PCP/th ratios of 13, 293, and 368, respectively. The binding affinities for the th-receptor are rationalized in terms of a model for the th-pharmacophore.


Asunto(s)
Fenciclidina/análogos & derivados , Fenciclidina/síntesis química , Receptores de Fenciclidina/metabolismo , Receptores sigma/metabolismo , Animales , Encéfalo/metabolismo , Cristalografía por Rayos X , Indicadores y Reactivos , Ligandos , Modelos Moleculares , Conformación Molecular , Estructura Molecular , Fenciclidina/química , Fenciclidina/metabolismo , Ensayo de Unión Radioligante , Ratas , Relación Estructura-Actividad , Receptor Sigma-1
16.
Pediatrics ; 75(5): 869-71, 1985 May.
Artículo en Inglés | MEDLINE | ID: mdl-3991273

RESUMEN

Methyl salicylate (oil of wintergreen) in the form of candy flavoring was ingested by a 21-month-old male infant who subsequently developed vomiting, lethargy, and hyperpnea. A "swallow" of the solution resulted in a serum salicylate concentration of 81 mg/dL six hours after ingestion. The infant was treated with parenteral fluids and sodium bicarbonate and he recovered rapidly. Hazards associated with salicylate use in this form include lack of parental awareness of the substance's toxic potential, the attractiveness of the candy-like odor, and the availability of the liquid in non-child-resistant packaging containing potentially lethal quantities.


Asunto(s)
Dulces/envenenamiento , Aromatizantes/envenenamiento , Salicilatos/envenenamiento , Humanos , Lactante , Masculino , Trastornos Respiratorios/inducido químicamente , Fases del Sueño/efectos de los fármacos , Vómitos/inducido químicamente
17.
Int J Oncol ; 17(4): 761-9, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-10995889

RESUMEN

p53 gene mutations are among the most common specific genetic alterations in human cancer. Inactivation of p53 and subsequent protein accumulation has been implicated in a variety of human malignancies and associated with prostate cancer progression. In this study, we assessed p53 protein overexpression and gene mutations in prostate carcinoma and investigated associations between p53 alterations and clinicopathological parameters, survival, and response to radiotherapy. We evaluated 58 archival formalin-fixed, paraffin-embedded prostate carcinomas to detect abnormal p53 nuclear protein accumulation using immunohistochemistry. p53 mutational status of tumor DNA was evaluated using polymerase chain reaction-single-strand conformation polymorphism analysis of exons 5-9 and confirmed by direct DNA sequencing. Univariate and multivariate statistical analysis was used to determine the association of p53 status with clinical characteristics and response to radiotherapy. Overexpression of p53 was detected in 42 (72%) of 58 primary prostate carcinomas, but was undetectable in 7 samples of benign prostatic hyperplasias or 5 samples of normal prostate tissue. p53 exon 5-9 mutations were detected in 8 (14%) of 58 patient specimens. p53 mutational status, but not overexpression, was associated with higher Gleason scores (p=0.0145). Neither p53 overexpression nor mutation was associated with clinical stage, biochemical disease-free probability, or predictive of response to radiotherapy. p53 protein accumulation was inversely associated with improved overall survival (p=0.0108). Our studies demonstrate that p53 protein accumulation is a frequent alteration in prostate cancer. The disparity between p53 protein overexpression and p53 exon 5-9 mutations suggests the possibility of mutations outside this region or stabilization of wild-type p53 by alternative mechanisms. In our patient population, p53 protein overexpression or mutational status was not predictive of outcome in patients treated with radiation therapy. Additional studies are needed to further evaluate the association between p53 protein overexpression and improved overall survival.


Asunto(s)
Neoplasias de la Próstata/patología , Proteína p53 Supresora de Tumor/genética , Adolescente , Análisis Mutacional de ADN , ADN de Neoplasias/química , ADN de Neoplasias/genética , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunohistoquímica , Masculino , Mutación , Estadificación de Neoplasias , Reacción en Cadena de la Polimerasa , Polimorfismo Conformacional Retorcido-Simple , Valor Predictivo de las Pruebas , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/radioterapia , Análisis de Supervivencia , Células Tumorales Cultivadas , Proteína p53 Supresora de Tumor/metabolismo
18.
Infect Dis Clin North Am ; 1(3): 575-90, 1987 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-3332886

RESUMEN

In summary, CSD is a relatively common cause of localized lymphadenopathy, with 80 per cent of cases occurring in children. This self-limited infection is caused by a small pleomorphic bacillus that has been identified in ocular granuloma, skin, and lymph node specimens. Unusual manifestations of the disease such as the oculoglandular disease of Parinaud, encephalopathy, or severe systemic disease occur in about ten per cent of patients. Management consists of symptomatic treatment and occasionally aspiration of a node that suppurates. The disease usually resolves spontaneously in 2 to 4 months.


Asunto(s)
Enfermedad por Rasguño de Gato , Enfermedad por Rasguño de Gato/diagnóstico , Enfermedad por Rasguño de Gato/epidemiología , Enfermedad por Rasguño de Gato/etiología , Enfermedad por Rasguño de Gato/terapia , Niño , Diagnóstico Diferencial , Humanos
19.
Urology ; 45(2): 320-2, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7855982

RESUMEN

A patient is presented whose first and sole evidence of metastatic transitional cell carcinoma of the bladder was pericardial metastasis with life-threatening cardiac tamponade. Definitive diagnosis and management was achieved with fluid cytology and video-assisted thoracic surgical pericardial biopsy and pericardial window.


Asunto(s)
Carcinoma de Células Transicionales/secundario , Neoplasias Cardíacas/secundario , Derrame Pericárdico/etiología , Neoplasias de la Vejiga Urinaria/patología , Anciano , Carcinoma de Células Transicionales/complicaciones , Neoplasias Cardíacas/complicaciones , Humanos , Masculino , Pericardio
20.
Urology ; 52(6): 1136-8, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9836571

RESUMEN

Primary bladder amyloidosis is a rare disease. Treatment recommendations are necessarily anecdotal. We report a case of a 52-year-old woman treated successfully with intravesical dimethyl sulfoxide instillation.


Asunto(s)
Amiloidosis/tratamiento farmacológico , Dimetilsulfóxido/administración & dosificación , Enfermedades de la Vejiga Urinaria/tratamiento farmacológico , Administración Intravesical , Femenino , Humanos , Persona de Mediana Edad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA