RESUMEN
Hepatocellular carcinoma (HCC) is a highly heterogeneous cancer, and resistant to both conventional and targeted chemotherapy. Recently, nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to decrease the incidence and mortality of different types of cancers. Here, we investigated the cellular bioactivities of a series of triazolothiadiazine derivatives on HCC, which have been previously reported as potent analgesic/anti-inflammatory compounds. From the initially tested 32 triazolothiadiazine NSAID derivatives, 3 compounds were selected based on their IC50 values for further molecular assays on 9 different HCC cell lines. 7b, which was the most potent compound, induced G2/M phase cell cycle arrest and apoptosis in HCC cells. Cell death was due to oxidative stress-induced JNK protein activation, which involved the dynamic involvement of ASK1, MKK7, and c-Jun proteins. Moreover, 7b treated nude mice had a significantly decreased tumor volume and prolonged disease-free survival. 7b also inhibited the migration of HCC cells and enrichment of liver cancer stem cells (LCSCs) alone or in combination with sorafenib. With its ability to act on proliferation, stemness and the migration of HCC cells, 7b can be considered for the therapeutics of HCC, which has an increased incidence rate of ~ 3% annually.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Animales , Apoptosis , Carcinoma Hepatocelular/patología , Neoplasias Hepáticas/patología , Sistema de Señalización de MAP Quinasas , Ratones , Ratones Desnudos , Estrés OxidativoRESUMEN
OBJECTIVE: Oral supplementation with curcumin demonstrated a beneficial effect on some ocular diseases, including uveitis and macular edema. This study aimed to evaluate the effectiveness and safety of a curcumin formulation with the hydrophilic carrier (CHC; Diabec®, Alfa Intes, Italy) as an adjuvant to standard steroid treatment in adults suffering from acute non-infectious uveitic macular edema (NIUME). PATIENTS AND METHODS: This was a monocenter prospective observational study carried out between January 2019 and May 2020 on consecutive patients with a new diagnosis of NIUME. Patients were treated with standard therapy or with a CHC add-on to standard treatment. The observation period for each patient was 12 months. The Best Corrected Visual Acuity (BCVA) and the Central Macular Thickness (CMT) were the primary outcomes; Foveal Avascular Zone (FAZ) and intraocular pressure (IOP) were also assessed, along with safety data. RESULTS: A total of 43 eyes of 26 patients were analyzed. CHC-treated eyes showed an improvement in mean BCVA from baseline (0.34 logMar) to T6 (0.20 logMar) and T12 (0.19 logMar; p≤0.05 and p≤0.01, respectively); CMT decreased from a mean of 320 µm (T0) to 278 µm (T6; p≤0.05) and 272 µm (T12; p≤0.01). A significant improvement of mean BCVA in the CHC group at T6 and T12 was reported compared to the control group (p≤0.01). FAZ and IOP showed no statistically significant variations in both groups. No adverse events were recorded. CONCLUSIONS: CHC as an adjuvant treatment improved the anatomical and functional outcomes, without significant side effects in eyes affected by the recent onset of NIUME, compared to the sole standard therapy.
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Curcumina , Edema Macular , Uveítis , Adulto , Curcumina/uso terapéutico , Glucocorticoides/uso terapéutico , Humanos , Inyecciones Intravítreas , Edema Macular/tratamiento farmacológico , Tomografía de Coherencia Óptica , Resultado del Tratamiento , Uveítis/diagnóstico , Uveítis/tratamiento farmacológico , Agudeza VisualRESUMEN
The use of Pressurized metered dose inhalers (pMDIs) for the treatment of asthma and other chronic obstructive pulmonary diseases is frequently associated with breath-actuation synchronization problems and poor pulmonary delivery, particularly amongst the pediatric and geriatric population groups. Spacers, or Valved Holding Chambers (VHCs), are frequently used to address these problems. However, the performance of spacers with different pMDIs is also highly variable and needs to be investigated. The purpose of the current study is to develop a computational fluid dynamics (CFD) model which can characterize multiphase multicomponent aerosol flow issuing from a commercial suspension-based pMDI into a spacer. The CFD model was initially calibrated against published experimental measurements in order to appropriately model the spray characteristics. This model was subsequently used to examine several combinations of inhaler, spacer and USP Throat geometries under different discharge rates of coflow air. The CFD model predictions compared favorably with experimental measurements. In particular, the predictions show, in accordance with experimental determinations, a decrease of drug retained by the spacers with increasing coflow air. The recirculation observed near the obstructions in axial path of the spray within either spacer is considered to be central for increasing spray retention and drug deposition behavior. Fluid flow patterns within the spacers were correlated with drug deposition behavior through a dimensionless variable, the Recirculation index (RCI). Bigger particles were found to be selectively retained within the spacer.
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Aerosoles , Espaciadores de Inhalación , Inhaladores de Dosis Medida , Administración por Inhalación , Diseño de EquipoRESUMEN
The full-resolution next generation impactor (NGI) and three abbreviated impactor systems were used to obtain the apparent aerodynamic particle size distribution (APSD) and other quality measures for marketed dry powder inhalers (DPIs) using the compendial method and efficient data analysis (EDA). APSD for the active pharmaceutical ingredient (API) in Spiriva® Handihaler®, Foradil® Aerolizer®, and Relenza® Diskhaler® was obtained using a full-resolution NGI at 39, 60, and 90 L/min, respectively. Two reduced NGI (rNGI) configurations, the filter-only configuration (rNGI-f) and the modified-cup configuration (rNGI-mc), and the fast-screening impactor (FSI) with appropriate inserts to provide a 5-µm cut size were evaluated. The fine particle dose (FPD) obtained using the FSI for Spiriva was statistically similar to that obtained using the full NGI. However, the FPD for both Foradil and Relenza obtained using the FSI was significantly different from that obtained using the full NGI. Despite this, no significant differences were observed for the fine particle fraction (FPF) obtained using the FSI relative to that obtained from the full NGI for any of the DPIs. The use of abbreviated impactor systems appears promising with good agreement observed with the full-resolution NGI, except for small differences observed for the rNGI-mc configuration. These small differences may be product- and/or flow rate-specific, and further evaluation will be required to resolve these differences.
Asunto(s)
Aerosoles , Inhaladores de Polvo Seco/métodos , Fumarato de Formoterol , Bromuro de Tiotropio , Zanamivir , Administración por Inhalación , Aerosoles/química , Aerosoles/farmacología , Fumarato de Formoterol/administración & dosificación , Fumarato de Formoterol/química , Humanos , Ensayo de Materiales/métodos , Inhaladores de Dosis Medida , Tamaño de la Partícula , Fármacos del Sistema Respiratorio/administración & dosificación , Fármacos del Sistema Respiratorio/química , Tecnología Farmacéutica/instrumentación , Tecnología Farmacéutica/métodos , Bromuro de Tiotropio/administración & dosificación , Bromuro de Tiotropio/química , Zanamivir/administración & dosificación , Zanamivir/químicaRESUMEN
The transcription factor JUN is frequently overexpressed in multiple genetic subtypes of acute myeloid leukemia (AML); however, the functional role of JUN in AML is not well defined. Here we report that short hairpin RNA (shRNA)-mediated inhibition of JUN decreases AML cell survival and propagation in vivo. By performing RNA sequencing analysis, we discovered that JUN inhibition reduces the transcriptional output of the unfolded protein response (UPR), an intracellular signaling transduction network activated by endoplasmic reticulum (ER) stress. Specifically, we found that JUN is activated by MEK signaling in response to ER stress, and that JUN binds to the promoters of several key UPR effectors, such as XBP1 and ATF4, to activate their transcription and allow AML cells to properly negotiate ER stress. In addition, we observed that shRNA-mediated inhibition of XBP1 or ATF4 induces AML cell apoptosis and significantly extends disease latency in vivo tying the reduced survival mediated by JUN inhibition to the loss of pro-survival UPR signaling. These data uncover a previously unrecognized role of JUN as a regulator of the UPR as well as provide key new insights into the how ER stress responses contribute to AML and identify JUN and the UPR as promising therapeutic targets in this disease.
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Leucemia Mieloide Aguda/metabolismo , Proteínas Proto-Oncogénicas c-jun/fisiología , Respuesta de Proteína Desplegada , Animales , Apoptosis , Proliferación Celular , Supervivencia Celular , Estrés del Retículo Endoplásmico , Humanos , Leucemia Mieloide Aguda/patología , Ratones , Proteínas Proto-Oncogénicas c-jun/antagonistas & inhibidores , ARN Interferente Pequeño/farmacología , Células Tumorales CultivadasRESUMEN
Newly designed triazolothiadiazines incorporating with structural motifs of nonsteroidal analgesic anti-inflammatory drugs were synthesized and screened for their bioactivity against epithelial cancer cells. Compounds with bioactivities less then â¼5µM (IC50) were further analyzed and showed to induce apoptotic cell death and SubG1 cell cycle arrest in liver cancer cells. Among this group, two compounds (1g and 1h) were then studied to identify the mechanism of action. These molecules triggered oxidative stress induced apoptosis through ASK-1 protein activation and Akt protein inhibition as demonstrated by downstream targets such as GSK3ß, ß-catenin and cyclin D1. QSAR and molecular docking models provide insight into the mechanism of inhibition and indicate the optimal direction of future synthetic efforts. Furthermore, molecular docking results were confirmed with in vitro COX bioactivity studies. This study demonstrates that the novel triazolothiadiazine derivatives are promising drug candidates for epithelial cancers, especially liver cancer.
Asunto(s)
Antineoplásicos/síntesis química , Regulación Neoplásica de la Expresión Génica , Tiadiazinas/síntesis química , Triazoles/síntesis química , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Ciclina D1/genética , Ciclina D1/metabolismo , Proteínas del Citoesqueleto/genética , Proteínas del Citoesqueleto/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Células HCT116 , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Hepatocitos/patología , Humanos , Concentración 50 Inhibidora , MAP Quinasa Quinasa Quinasa 5/genética , MAP Quinasa Quinasa Quinasa 5/metabolismo , Células MCF-7 , Simulación del Acoplamiento Molecular , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Estrés Oxidativo/efectos de los fármacos , Estructura Secundaria de Proteína , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Relación Estructura-Actividad Cuantitativa , Transducción de Señal , Tiadiazinas/farmacología , Triazoles/farmacología , beta Catenina/genética , beta Catenina/metabolismoRESUMEN
Pruritus can be the dominant symptom of cholestatic liver disease but is difficult to treat since unraveling its pathophysiology is a great challenge. Serum autotaxin activity correlates with pruritus intensity, but its causal relationship, expression pattern and exact mode of action during cholestasis remain to be established. The anion exchange resin cholestyramine, the PXR agonist rifampicin, the opioid antagonist naltrexone and the serotonine reuptake inhibitor sertraline are recommended by evidence-based guidelines as stepwise therapeutic approaches to treat itch in cholestasis. Rifampicin, the most effective antipruritic agent in cholestatic itch, has been shown to reduce autotaxin transcription in vitro. Experimental approaches include UVB phototherapy, extracorporeal albumin dialysis, nasobiliary drainage and in desperate cases even liver transplantation. Relevant clinical observations along with the different metabolic, neurologic and endocrine targets of available therapies in cholestatic pruritus are reviewed here.
Asunto(s)
Antipruriginosos/uso terapéutico , Colestasis , Hidrolasas Diéster Fosfóricas/metabolismo , Prurito , Rifampin/uso terapéutico , Resinas de Intercambio Aniónico/uso terapéutico , Colestasis/complicaciones , Colestasis/metabolismo , Resina de Colestiramina/uso terapéutico , Terapia Combinada , Diálisis/métodos , Manejo de la Enfermedad , Inhibidores Enzimáticos/uso terapéutico , Humanos , Antagonistas de Narcóticos/uso terapéutico , Fototerapia/métodos , Pronóstico , Prurito/tratamiento farmacológico , Prurito/etiología , Prurito/metabolismo , Prurito/fisiopatología , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Índice de Severidad de la Enfermedad , Resultado del TratamientoRESUMEN
Metallothionein and metal content (Cd, Zn, Hg, Cu, Fe, Pb and Mn) were determined in various organs of commercially available eel (Anguilla anguilla) of similar size obtained from a local farm and from The Albufera Lake in Valencia (Spain). Farmed fish showed statistically significant higher Cd concentrations in liver and kidney whereas wild individuals had higher levels of Pb in blood and Zn in kidney. Significant positive correlations were found between metallothionein and Cd in kidney of farmed eel and between metallothionein and Cu in liver of wild ones. No statistically significant differences were found between the two populations in the concentration of any of the metals analyzed in muscle and in all instances these levels were lower than the limits established by the Spanish legislation for fish destined for human consumption.
Asunto(s)
Acuicultura , Anguilas , Metalotioneína/análisis , Metales/análisis , Animales , Guías como AsuntoRESUMEN
A unique feature of human soft tissue liposarcoma is a stable (12;16)(q13;p11) translocation observed mainly in myxoid and roundcell liposarcomas. This translocation results in FUS/CHOP fusion transcripts with a corresponding oncogenic protein. We hypothesised that genes downstream of FUS/CHOP might serve as attractive candidates for novel tumour associated antigens. Among a panel of analysed genes, only pentraxin related gene (PTX3) demonstrated high expression in liposarcomas as compared to normal tissues. The analysis of RNA and protein expression demonstrated concordant results. However, the level of RNA and protein overexpression did not correlate in all cases. Finally, PTX3 expression was not related to presence of a FUS/CHOP fusion transcript within the liposarcoma tissues. PTX3 has been associated with adipocyte differentiation and now, additionally, is characterised by a markedly increased expression in human soft tissue liposarcoma. This finding mandates further research efforts to clarify the exact role of PTX3 in liposarcoma oncogenesis.
Asunto(s)
Proteína C-Reactiva/metabolismo , Liposarcoma/genética , Proteínas de Neoplasias/metabolismo , Componente Amiloide P Sérico/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Western Blotting , Estudios de Cohortes , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Proteínas de Fusión Oncogénica/metabolismo , Proteína FUS de Unión a ARN/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Transcripción CHOP/metabolismo , Translocación GenéticaRESUMEN
Trends in new case-detection are analysed by reviewing the demographic and leprosy epidemiological data and current indicators in Subarnapur district, Orissa State and India. Population-specific new case-detection rates were calculated for analysis. The trend of skin-smear positive cases over a period of 10 years was reviewed in respect of smear positive cases of 1991. During the years 2002 to 2004, a sudden fall was noticed in the new cases detected in both India and Orissa state, whereas the decline in Subarnapur district was more gradual. The fall in the female-specific new case-detection rates is found to be rapid from 11 to 2.5 over the last three years. This also indirectly indicated the health-seeking behaviour of women in accessing health services and hence required a changed strategy. A similar rapid decline was observed in child-specific new case-detection rates. On analysiS, the decline of highly bacilliferous cases from 1991 to 2001 was found to be statistically significant. The analysis also brought out the fact that cases with bacterial index of 1+, 2+ and 3+, though small in numbers, were detected during the last three years indicating continued presence of cases with low bacterial density in the community. The review indicates a definite decline in the occurrence of new cases in all groups. Caution needs to be exercised about continued presence of cases with low bacterial index though in small numbers. The rapid decrease of cases in all groups during the years 2004 and 2005 warrants meticulous surveillance. The surveillance activities could include monitoring of population-specific new case-detection rates and skin-smear positive cases at district and state levels in order to advise on leprosy eradication programme strategies.
Asunto(s)
Control de Enfermedades Transmisibles/tendencias , Lepra/epidemiología , Vigilancia de Guardia , Adulto , Distribución por Edad , Niño , Control de Enfermedades Transmisibles/estadística & datos numéricos , Femenino , Predicción , Humanos , Incidencia , India/epidemiología , Lepra/mortalidad , Lepra/patología , Masculino , Prevalencia , Distribución por SexoRESUMEN
The molecular mechanisms leading to adrenocortical tumorigenesis have been only partially elucidated so far. Because the pituitary hormone ACTH, via activation of the cAMP pathway, regulates both cell proliferation/differentiation and steroid synthesis in the adrenal cortex, in this study we focused on the cAMP-dependent transcription factors cAMP responsive element modulator (CREM) and cAMP responsive element binding protein (CREB). We studied CREM and CREB expression by RT-PCR in human normal adrenal cortex (n = 3), adrenocortical adenomas (n = 8), and carcinomas (n = 8). We found transcripts corresponding to the isoforms alpha, beta, gamma, and tau2 of the CREM gene in all of the normal adrenal tissues, in the adenomas, and in seven of eight carcinomas. On the other hand, mRNA for the inducible cAMP early repressor isoforms, which derive from an internal promoter of CREM gene, was detected in the normal adrenal and in seven of eight adenomas, but in only three of eight carcinomas. Similarly, CREB transcripts were readily detectable in all normal adrenals and adenomas, whereas they were not found in four of eight adrenal carcinomas. To further characterize the carcinomas, telomerase activity and the expression of the ACTH receptor gene were determined. Telomerase activity in the carcinomas resulted in levels significantly higher than in the adenomas, whereas the levels of ACTH receptor mRNA were lower in the carcinomas. No correlation was found in the carcinomas between the levels of the ACTH receptor transcript and the loss of expression of CREB/inducible cAMP early repressor, suggesting that this alteration is not secondary to an upstream disregulation at the receptor level. In conclusion, our results suggest that an alteration in cAMP signaling may be associated with malignancies of the adrenal cortex.
Asunto(s)
Adenoma/metabolismo , Neoplasias de la Corteza Suprarrenal/metabolismo , Corteza Suprarrenal/metabolismo , Carcinoma/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/biosíntesis , Proteínas Represoras/biosíntesis , Adenoma/enzimología , Corteza Suprarrenal/enzimología , Neoplasias de la Corteza Suprarrenal/enzimología , Adulto , Carcinoma/enzimología , Femenino , Gliceraldehído-3-Fosfato Deshidrogenasas/biosíntesis , Humanos , Hidrocortisona/metabolismo , Masculino , Persona de Mediana Edad , Receptores de Corticotropina/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Telomerasa/metabolismo , Transcripción Genética/fisiologíaRESUMEN
General Protein/Mass Analysis for Windows (GPMAW) is a valuable piece of software for any molecular biologist, biochemist or mass spectrometrist wishing to analyze protein or peptide sequences. All steps from the acquisition of protein sequence from a built-in web interface, to proteolytic digests, theoretical peptide fragmentation, detailed annotation of sequences and secondary structure prediction, can be performed rapidly and intuitively without first having to spend days reading manuals.
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Péptidos/análisis , Proteínas/análisis , Secuencia de Aminoácidos , Biología Computacional , Simulación por Computador , Bases de Datos de Proteínas , Internet , Modelos Teóricos , Valor Predictivo de las Pruebas , Procesamiento Proteico-Postraduccional/fisiología , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Análisis de Secuencia de Proteína/métodos , Programas InformáticosRESUMEN
More than two decades ago Marilyn Kozak proposed the scanning model of translation initiation, whereby translation is initiated at the first AUG codon that is in a particular context. In this article, we re-examine the context of initiator codons using a large dataset of curated human transcripts. We find that more than 40% of transcripts contain AUG codons upstream of the actual start codon and that most authentic AUGs contain three or more mismatches from the consensus sequence, CCACCaugG. Also, in a large fraction of transcripts, the sequences surrounding the initiator codon deviate more from the consensus than those surrounding upstream AUGs, indicating that translation initiation from downstream AUGs is more common than generally believed.
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Codón Iniciador , Biosíntesis de Proteínas , Regiones no Traducidas 5'/química , Animales , Secuencia de Consenso , Citocinas/biosíntesis , Citocinas/genética , Citosol/metabolismo , Sustancias de Crecimiento/biosíntesis , Sustancias de Crecimiento/genética , Humanos , Señales de Clasificación de Proteína , ARN Mensajero/química , Receptores de Superficie Celular/biosíntesis , Receptores de Superficie Celular/genética , Vertebrados/genética , Vertebrados/metabolismoRESUMEN
In about 30-40% of GH-secreting adenomas, gain-of-function mutations of the Gsalpha gene, which convert this gene into an oncogene termed gsp, occur. Gsalpha mutations have been related to pituitary tumorigenesis. We focused on 2 nuclear transcription factors that are final targets of the cAMP-dependent pathway and are positively regulated by cAMP signaling, i.e. the cAMP-responsive element binding protein (CREB) and the inducible cAMP early repressor (ICER), that derives from alternative splicing of cAMP-responsive element modulator gene. We examined 21 GH-secreting adenomas, 8 with (gsp(+)) and 13 without (gsp(-)) a mutated Gsalpha. Analysis of CREB and ICER I/II messenger RNA revealed that the levels of both transcripts were higher in gsp(+) than in gsp(-) tumors (CREB/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mean optical density +/- SE, 2.34 +/- 0.36 in gsp(+) vs. 0.99 +/- 0.22 in gsp(-), P = 0.003; ICER I/GAPDH, 0.53 +/- 0.15 in gsp(+) vs. 0.14 +/- 0.07 in gsp(-), P = 0.01; ICER II/GAPDH, 1.5 +/- 0.21 in gsp(+) vs. 0.83 +/- 0.13 in gsp(-), P = 0.01), although a few cases in both groups did not display this pattern of expression. Moreover, no positive correlation between the levels of CREB and ICER transcripts was observed, suggesting the possible presence of alterations in the mechanisms by which cAMP signaling directs the expression of CREB and/or ICER genes. Our results indicate a complex pattern of expression of nuclear transcription factors that mediate cAMP action in both gsp(+) and gsp(-) tumors, suggesting that, beside Gsalpha gene mutations, different and partially unknown molecular events may contribute to the pathogenesis of these tumors.
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Adenoma/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Proteínas de Unión al ADN/genética , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Hormona de Crecimiento Humana/metabolismo , Mutación , Neoplasias Hipofisarias/metabolismo , Proteínas Represoras , Adolescente , Adulto , Anciano , Secuencia de Bases , Modulador del Elemento de Respuesta al AMP Cíclico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa InversaAsunto(s)
Biología Computacional , Bases de Datos Genéticas , Programas Informáticos , Secuencia de Bases , Biología Computacional/normas , Bases de Datos Genéticas/normas , Almacenamiento y Recuperación de la Información , Internet , Estructura Terciaria de Proteína , ARN Mensajero , Alineación de SecuenciaRESUMEN
The effects of sublethal doses of lead (as acetate) on blood parameters of adult male Bufo arenarum were studied. Toads received one single injection with 10, 25, 50 or 100 mg/kg of body weight, equivalent to approximately 1/90-1/10 of the 120 h-LD50; seven days after the injections, the hematocrit and the blood delta-aminolevulinic acid dehydratase (ALAD) activity were measured. Hematocrit of lead-injected animals did not exhibit significant changes respective to controls that received sodium acetate (range 29.8-38.8%). Blood lead concentrations were positively and significantly correlated with the injected metal doses. Blood ALAD activity declined proportionately to the doses of the metal as well as to its whole blood concentration. Because of its sensitivity and specificity, it was concluded that the activity of delta-ALAD may be adopted as a reliable biomarker of Bufo arenarum experimental lead intoxication.
Asunto(s)
Bufo arenarum/sangre , Plomo/sangre , Porfobilinógeno Sintasa/sangre , Animales , Biomarcadores , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/toxicidad , Hematócrito , Masculino , Compuestos Organometálicos/administración & dosificación , Compuestos Organometálicos/toxicidad , Porfobilinógeno Sintasa/antagonistas & inhibidores , Sensibilidad y Especificidad , Contaminantes Químicos del Agua/toxicidadRESUMEN
Synthesis and properties of two new macrobiomolecular cross-linking reagents, bis(phenoxycarbonylethyl) phosphinic acid (BPCEP) and bis(3-nitrophenoxycarbonylethyl)phosphinic acid (BNCEP), have been reported. The reagents were successfully employed to cross-link human hemoglobin under oxygenated conditions. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), high performance liquid chromatography (HPLC), and fast protein liquid chromatography (FPLC) analyses of the reaction products indicated that the cross-link was intramolecular in nature, and that it was between the two beta subunits of hemoglobin in each case. The products were purified by DEAE-cellulose chromatography, and the purified material was employed for oxygen-binding assessments. The oxygen equilibrium curve of the cross-linked material, in each case, was right-shifted toward lower oxygen affinity as desired. The sigmoidal shapes of oxygen curves, in each case, suggested retainment of oxygen-binding cooperativity, although considerably lower than that of the native hemoglobin
Asunto(s)
Hemoglobinas/química , Organofosfonatos/química , Ácidos Fosfínicos/química , Cromatografía Líquida de Alta Presión , Reactivos de Enlaces Cruzados , Humanos , Organofosfonatos/síntesis química , Ácidos Fosfínicos/síntesis químicaRESUMEN
The effects on red blood cells of a single sublethal dose of Pb of 100 mg kg-1 administrated to adult Bufo arenarum were studied. The blood d-aminolevulinic acid dehydratase (d-ALAD) activity, the red blood cell (RBC) osmotic fragility (OF), and the hematocrit (Hct) were measured in control and lead poisoned toad. The enzyme d-ALAD is considered as a specific biomarker for human and animals lead exposure. In Bufo, lead also provoked a significant decrease in the d-ALAD activity without changes in the Hct. OF test was used to compare the impact of Pb on the extent of the RBC hemolysis produced by osmotic stress. Experimental data (absorbance of solubilized hemoglobin and [NaCl]) were fitted to the Orcutt et al. equation (1995) that allows a precise characterization of the parameters involved in OF. In blood from injected toads, the OF resulted significantly reduced. These changes were interpreted as a consequence of alterations in the composition and conformation of the RBC membrane due to Pb, as it was described for human erythrocytes.