RESUMEN
BACKGROUND: Although immunotherapy is thought to be a promising cancer treatment, most patients do not respond to immunotherapy. In this post hoc analysis of a phase 1/2 study, associations of programmed death ligand 1 (PD-L1), PD-L2, and HLA class I expressions with responses to dendritic cells (DCs)-based immunotherapy were investigated in patients with advanced sarcoma. METHODS: This study enrolled 35 patients with metastatic and/or recurrent sarcomas who underwent DC-based immunotherapy. The associations of PD-L1, PD-L2, and HLA class I expressions in tumor specimens, which were resected before immunotherapy, with immune responses (increases of IFN-γ and IL-12) and oncological outcomes were evaluated. RESULTS: Patients who were PD-L2 (+) showed lower increases of IFN-γ and IL-12 after DC-based immunotherapy than patients who were PD-L2 (-). The disease control (partial response or stable disease) rates of patients who were PD-L1 (+) and PD-L1 (-) were 0% and 22%, respectively. Disease control rates of patients who were PD-L2 (+) and PD-L2 (-) were 13% and 22%, respectively. Patients who were PD-L1 (+) tumors had significantly poorer overall survival compared with patients who were PD-L1 (-). No associations of HLA class I expression with the immune response or oncological outcomes were observed. CONCLUSIONS: This study suggests that PD-L1 and PD-L2 are promising biomarkers of DC-based immunotherapy, and that addition of immune checkpoint inhibitors to DC-based immunotherapy may improve the outcomes of DC-based immunotherapy.
Asunto(s)
Antígeno B7-H1/metabolismo , Antígenos de Histocompatibilidad Clase I/metabolismo , Inmunoterapia , Proteína 2 Ligando de Muerte Celular Programada 1/metabolismo , Sarcoma/terapia , Adulto , Biomarcadores de Tumor/metabolismo , Células Dendríticas , Femenino , Humanos , Interferón gamma/metabolismo , Interleucina-12/metabolismo , Masculino , Sarcoma/inmunología , Sarcoma/mortalidad , Sarcoma/patología , Resultado del TratamientoRESUMEN
El síndrome de Down o trisomía 21 es la alteración genética más frecuente en el ser humano; uno de cada 600-700 recién nacidos vivos es afectado por este síndrome. Éste se caracteriza por la presencia de un cromosoma adicional en el par 21, el cual provoca disminución generalizada en el crecimiento y discapacidad intelectual. Diversas manifestaciones craneofaciales y bucales han sido descritas en la literatura. El principal padecimiento bucal reportado en este grupo de pacientes es la enfermedad periodontal. Objetivo: Establecer cuidados bucales preventivos en el desarrollo de la enfermedad periodontal en pacientes adolescentes con síndrome de Down. Presentación del caso: Paciente indígena masculino de 15 años de edad con trisomía 21, bilingüe. Presenta cardiopatía congénita, hipertensión pulmonar y síndrome nefrótico, así como erupción ectópica y ausencias congénitas dentales, oclusión clase III de Angle, mordida cruzada unilateral anterior y posterior, respiración bucal, eversión labial, lengua y labios Asurados, clinodactilia y gingivitis localizada. El manejo de conducta se llevó a cabo a través de la técnica «decir-mostrar-hacer¼ y control de voz. El tratamiento inicial consistió en técnica de cepillado de barrido asistido por los padres, uso del hilo dental, CPDB (Dento Bacterial Plaque Control) (100%) y aplicación tópica de barniz de fluoruro. Se recomendó a los padres la aplicación en el hogar de un gel bioadhesivo (Perioxidin®) para la rehabilitación oral. Conclusiones: El aspecto más relevante fue la disminución de la cantidad de placa dentobacteriana reportada en controles posteriores (40%).
Down's syndrome or trisomy 21 is man's most frequent genetic disorder. It affects one out of 600-700 live births. It is characterized by the presence of an additional chromosome at the 21 pair which elicits generalized decrease of growth as well as intellectual disability. In scientific literature there are many reports of cranio-facial and oral manifestations of this disorder. Chief oral condition reported in this group of patients is periodontal disease. Objective: Establishment of preventive oral care for the development of periodontal disease in adolescent patients afflicted with Down's syndrome. Case presentation: 15 year old Mexican-Indian male patient with trisomy 21. The patient was bilingual, afflicted with congenital heart disease, pulmonary hypertension and nephrotic syndrome. The patient equally presented ectopic dental eruption as well as congenital dental absences, Angle's class III occlusion, anterior and posterior unilateral crossbite, oral respiration, labial eversion, fissured tongue and lips, clinodactyly and localized gingivitis. Behavior management was achieved with the «show-tell-do¼ technique alongside with voice control. Initial treatment consisted on sweeping brushing technique with parental assistance, use of dental floss (Dento Bacterial Plaque Control [DBPC]) (100%) as well as topical application of fluoride varnish. It was recommended to the parents they should use home applications of bioadhesive gel (Perioxidin®). After these measures, oral rehabilitation was undertaken. Conclusions: The most relevant aspect of the treatment was the decrease (40%) in bacterial plaque reported in later control visits.
RESUMEN
The interleukin (IL)-13-mediated goblet cell response is the major host effector system involved in the expulsion of Nippostrongylus brasiliensis. Lactic dehydrogenase virus (LDV) induced higher levels of N. brasiliensis egg production compared with controls, but the effect of LDV infection on worm expulsion of, and goblet cell and IL-13 responses to, N. brasiliensis have not been studied. In this study, the effects of LDV infection on these host responses against N. brasiliensis were examined. Mice with chronic LDV infection showed significantly lower worm expulsion rates than non-LDV-infected mice after N. brasiliensis infection, and there were no significant differences in the ratio of female versus male adult worms between control and LDV-infected mice. The number of goblet cells in LDV-infected mice was significantly lower than that in controls. In addition, the levels of IL-13 gene expression in lymph nodes were significantly lower in LDV-infected mice compared with controls. These results suggest that LDV infection reduces the protective immune responses against N. brasiliensis infection by the suppression of IL-13 production.
Asunto(s)
Infecciones por Arterivirus/complicaciones , Virus Elevador de Lactato Deshidrogenasa , Nippostrongylus , Infecciones por Strongylida/inmunología , Animales , Femenino , Células Caliciformes/citología , Interleucina-13/análisis , Intestino Delgado/parasitología , Pulmón/parasitología , Masculino , Ratones , Ratones Endogámicos BALB C , Nippostrongylus/genética , Nippostrongylus/crecimiento & desarrollo , Nippostrongylus/aislamiento & purificación , Ratas , Ratas Sprague-Dawley , Infecciones por Strongylida/complicaciones , Infecciones por Strongylida/parasitologíaRESUMEN
The influence of flufenamic acid and other nonsteroidal anti-inflammatories on sulfate transport in the liver was investigated. The experimental system was the isolated perfused rat liver. Perfusion was accomplished in an open, nonrecirculating system. The perfusion fluid was Krebs/Henseleit-bicarbonate buffer (pH 7.4), saturated with a mixture of oxygen and carbon dioxide (95:5) by means of a membrane oxygenator and heated to 37 degrees C. Sulfate transport (equilibrium exchange) was measured by employing the multiple-indicator dilution technique with simultaneous injection (impulse input) of [35S]sulfate. [3H]sucrose (indicator for the distribution of the sinusoidal transit times), and [3H]water (indicator for the total aqueous space). Analysis was accomplished by means of a space-distributed variable transit time model. Flufenamic acid and other anti-inflammatories inhibited sulfate transport in the liver. For a concentration of 100 microM, the following decreasing series of potency could be established: flufenamic acid (53.4 +/- 2.9%) > niflumic acid (41.1 +/- 1.4%) > mefenamic acid (35.6 +/- 3.3%) > piroxicam (16.6 +/- 1.9%) > naproxen (13.5 +/- 8.4)%) nimesulide (11.6 +/- 5.8%). Inhibition of sulfate transport by flufenamic acid was clearly concentration dependent; 250 microM flufenamic acid produced more than 95% inhibition. Flufenamic acid in the range between 50 and 250 microM did not affect the mean transit times of tritiated water (t water) and [3H]sucrose (t suc), the same applying to all other anti-inflammatory agents (100 microM) tested in this work. This means that these agents do not affect vascular and cellular spaces, even when present at high concentrations. The ratio of the intra- to extracellular sulfate concentrations ([C]i/[C]e), generally between 0.4 and 0.5 under control conditions, was affected only by 250 microM flufenamic acid and 100 microM niflumic acid. In the first case, this phenomenon is possibly due to the high degree of transport inhibition (more than 95%), which does not allow a uniform tracer distribution over the whole cellular space during a single passage through the liver. The degree of inhibition of sulfate transport by 100 microM flufenamic acid was a function of the concentration of nontracer sulfate. With sulfate in the range between 1.2 and 25 mM, the inhibition degree increased linearly with the concentration. In the presence of flufenamic acid, the saturation curve of equilibrium exchange showed a substrate inhibition-like phenomenon, which was absent in the control curve. As inhibitors of sulfate transport in hepatocytes, flufenamic and niflumic acids are less active than in erythrocytes by a factor of 10(2). This observation is most probably indicative of structural differences between the hepatic sulfate carrier and the anion carrier of erythrocytes. It is unlikely that the action of flufenamic acid and its analogs on sulfate transport is a consequence of energy metabolism inhibition. Nimesulide is as active as flufenamic or niflumic acid in inhibiting energy metabolism but considerably less efficient as an inhibitor of sulfate transport. Our results as well as literature data reveal that the interactions of the nonsteroidal anti-inflammatories with the liver membranes and intracellular structures are ample and complex. Even at high concentrations, however, these interactions are not so intense as to change the vascular and cellular spaces.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Ácido Flufenámico/farmacología , Hígado/efectos de los fármacos , Sulfatos/farmacocinética , Animales , Transporte Biológico , Relación Dosis-Respuesta a Droga , Técnicas In Vitro , Hígado/metabolismo , Masculino , Ácido Mefenámico/farmacología , Naproxeno/farmacología , Ácido Niflúmico/farmacología , Perfusión , Piroxicam/farmacología , Ratas , Ratas Wistar , Sulfonamidas/farmacología , Radioisótopos de Azufre , Factores de TiempoRESUMEN
The oxidative susceptibility of plasma obtained from rats after intragastric administration of quercetin was studied to know whether or not quercetin acts as an in vivo antioxidant after metabolic conversion. Quercetin was raised in the rat blood plasma essentially as glucuronide and/or sulfate conjugates. The plasma obtained from rats after quercetin administration was more resistant against copper sulfate-induced lipid peroxidation than the control plasma on the basis of the accumulation of cholesteryl ester hydroperoxides and the consumption of alpha-tocopherol. The results strongly suggest that some conjugated metabolites of quercetin act as effective antioxidants when plasma is subject to metal ion-induced lipid peroxidation.
Asunto(s)
Antioxidantes/farmacología , Flavonoles , Peroxidación de Lípido/efectos de los fármacos , Quercetina/sangre , Quercetina/farmacología , Animales , Ésteres del Colesterol/sangre , Sulfato de Cobre/farmacología , Glucuronatos/sangre , Masculino , Oxidación-Reducción , Quercetina/análogos & derivados , Ratas , Ratas Wistar , Vitamina ERESUMEN
1. The influence of Ca2+ on the effects of glucagon on glycolysis was investigated in the isolated perfused rat liver. Livers from fed rats were perfused in an open system with Krebs/Henseleit-bicarbonate buffer (pH 7.4). Glucose release, lactate plus pyruvate production (glycolysis) and oxygen uptake were measured. The following results were obtained: 2. In livers perfused with Ca(2+)-free Krebs/Henseleit-bicarbonate buffer and after depletion of the intracellular pools, the initial and transient stimulation of glycolysis, which is normally observed shortly after the onset of glucagon infusion, was more pronounced when compared to livers perfused with normal perfusion fluid (2.5 mM Ca2+) and without previous depletion of the intracellular pools (controls); the subsequent inhibition of glycolysis was delayed in Ca(2+)-free perfused livers and was less pronounced in comparison with the controls at the end of the glucagon infusion period (20 min). 3. Perfusion with a Ca(2+)-free medium supplemented with EDTA, without previous depletion of the intracellular pools, also produced a substantial reduction in the effects of glucagon on glycolysis. 4. Ca(2+)-free perfusion did not affect the stimulative action of glucagon on glucose release (glycogenolysis) and oxygen uptake. 5. Glycolysis inhibition by cAMP also was abolished in Ca(2+)-free perfused livers, and the initial stimulation was enhanced. 6. Mn2+, a metal ion known as a competitor of Ca2+, considerably reduced the action of glucagon on glycolysis; Mn2+ did not affect the basal rates of glycolysis. 7. Sr2+, a metal ion that is often recognized as Ca2+ by several biological structures and processes, increased the inhibitory action of glucagon on glycolysis. 8. Several organic compounds, which directly or indirectly take part in Ca2+ fluxes, were also able to diminish (e.g., verapamil) or even to abolish (carbenoxolone) the inhibitory action of glucagon on glycolysis. 9. It was concluded that, under the conditions of the living cell, Ca2+ is important for glycolysis inhibition by glucagon. In principle at least, the results can be explained in terms of the known Ca2+ dependencies of several protein kinases and protein phosphatases.
Asunto(s)
Calcio/metabolismo , Fármacos Gastrointestinales/farmacología , Glucagón/farmacología , Glucólisis/efectos de los fármacos , Hígado/efectos de los fármacos , Animales , Calcio/farmacología , AMP Cíclico/metabolismo , AMP Cíclico/farmacología , Hígado/metabolismo , Masculino , Ratas , Ratas WistarRESUMEN
The following aspects were investigated in the present work: (a) the action of flufenamic acid on hepatic metabolism (oxygen uptake, glycolysis, gluconeogenesis, uricogenesis and glycogenolysis), (b) the action of flufenamic acid on the cellular adenine nucleotide levels, and (c) the transport and distribution space of flufenamic acid in the liver parenchyma. The experimental system was the isolated perfused rat liver. Perfusion was accomplished in an open, non-recirculating system. The perfusion fluid was Krebs/Henseleit-bicarbonate buffer (pH 7.4), saturated with a mixture of oxygen and carbon dioxide (95:5) by means of a membrane oxygenator and heated to 37 degrees C. The distribution space of flufenamic acid was measured by means of the multiple-indicator dilution technique with constant infusion (step input) of [3H]water plus flufenamic acid. The results of the present work indicate that the metabolic effects of flufenamic acid are the consequence of an uncoupling of oxidative phosphorylation, a conclusion based on the following observations: (a) flufenamic acid increased oxygen uptake, a common property of all uncouplers; (b) the drug also increased glycolysis and glycogenolysis in livers from fed rats (these are expected compensatory phenomena for the decreased mitochondrial ATP formation); (c) flufenamic acid inhibited glucose production from fructose, an energy-dependent process; (d) the cellular ATP levels were decreased by flufenamic acid whereas the AMP levels were increased; and (e) the total adenine nucleotide content was decreased by flufenamic acid and uric acid production was stimulated. Indicator-dilution experiments with flufenamic acid revealed that this substance undergoes flow-limited distribution in the liver and that its apparent distribution space greatly exceeds the aqueous space of the liver. Flufenamic acid changed its behaviour when the portal concentration was increased from 25 to 50 microM. At 25 microM the initial upslope of the outflow profile clearly preceded that of all other concentrations. From the trend of the curves obtained with 50, 100 and 250 microM, one would expect an initial upslope situated at the right of the 50-microM curve. Furthermore, the time of appearance of flufenamic acid in the outflowing perfusate was practically the same irrespective of the portal concentration. For theoretical reasons one would expect progressively longer appearance times when the portal concentration was decreased. It is possible that the amount of flufenamic acid bound to the cell membranes during the early stages of the infusion produced changes that enabled these structures to bind a larger quantity of the drug than originally possible.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Ácido Flufenámico/farmacología , Hígado/efectos de los fármacos , Hígado/metabolismo , Nucleótidos de Adenina/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Fructosa/metabolismo , Glucógeno Hepático/metabolismo , Masculino , Oxígeno/metabolismo , Perfusión , Ratas , Ratas Wistar , Distribución Tisular , Ácido Úrico/metabolismoRESUMEN
The influence of Ca2+ on hepatic gluconeogenesis was measured in the isolated perfused rat liver at different cytosolic NAD(+)-NADH potentials. Lactate and pyruvate were the gluconeogenic substrates and the cytosolic NAD(+)-NADH potentials were changed by varying the lactate to pyruvate ratios from 0.01 to 100. The following results were obtained: a) gluconeogenesis from lactate plus pyruvate was not affected by Ca(2+)-free perfusion (no Ca2+ in the perfusion fluid combined with previous depletion of the intracellular pools); gluconeogenesis was also poorly dependent on the lactate to pyruvate ratios in the range of 0.1 to 100; only for a ratio equal to 0.01 was a significantly smaller gluconeogenic activity observed in comparison to the other ratios. b) In the presence of Ca2+, the increase in oxygen uptake caused by the infusion of lactate plus pyruvate at a ratio equal to 10 was the most pronounced one; in Ca(2+)-free perfusion the increase in oxygen uptake caused by lactate plus pyruvate infusion tended to be higher for all lactate to pyruvate ratios; the most pronounced difference was observed for lactate/pyruvate ratio equal to 1. c) In the presence of Ca2+ the effects of glucagon on gluconeogenesis showed a positive correlation with the lactate to pyruvate ratios; for a ratio equal to 0.01 no stimulation occurred, but in the 0.1 to 100 range stimulation increased progressively, producing a clear parabolic dependence between the effects of glucagon and the lactate to pyruvate ratio. d) In the absence of Ca2+ the relationship between the changes caused by glucagon in gluconeogenesis and the lactate to pyruvate ratio was substantially changed; the dependence curve was no longer parabolic but sigmoidal in shape with a plateau beginning at a lactate/pyruvate ratio equal to 1; there was inhibition at the lactate to pyruvate ratios of 0.01 and 0.1 and a constant stimulation starting with a ratio equal to 1; for the lactate to pyruvate ratios of 10 and 100, stimulation caused by glucagon was much smaller than that found when Ca2+ was present. e) The effects of glucagon on oxygen uptake in the presence of Ca2+ showed a parabolic relationship with the lactate to pyruvate ratios which was closely similar to that found in the case of gluconeogenesis; the only difference was that inhibition rather than stimulation of oxygen uptake was observed for a lactate to pyruvate ratio equal to 0.01; progressive stimulation was observed in the 0.1 to 100 range. f) In the absence of Ca2+ the effects of glucagon on oxygen uptake were different; the dependence curve was sigmoidal at the onset, with a well-defined maximum at a lactate to pyruvate ratio equal to 1; this maximum was followed by a steady decline at higher ratios; at the ratios of 0.01 and 0.1 inhibition took place; oxygen uptake stimulation caused by glucagon was generally lower in the absence of Ca2+ except when the lactate to pyruvate ratio was equal to 1. The results of the present study demonstrate that stimulation of gluconeogenesis by glucagon depends on Ca2+. However, Ca2+ is only effective in helping gluconeogenesis stimulation by glucagon at highly negative redox potentials of the cytosolic NAD(+)-NADH system. The triple interdependence of glucagon-Ca(2+)-NAD(+)-NADH redox potential reveals highly complex interrelations that can only be partially understood at the present stage of knowledge.
Asunto(s)
Calcio/fisiología , Citosol , Glucagón/fisiología , Gluconeogénesis/fisiología , NAD/fisiología , Oxidación-Reducción , Animales , Hígado , Perfusión , RatasRESUMEN
The influence of Ca2+ on hepatic gluconeogenesis was measured in the isolated perfused rat liver at different cytosolic NAD+-NADH potentials. Lactate and pyruvate were the gluconeogenic substrates and the cytosolic NAD+-NADH potentials were changed by varying the lactate to pyruvate rations from 0.01 to 100. The following results were obtained: a) gluconeogenesis from lactate plus pyruvate was not affected by Ca2+-free perfusion (no Ca2+ in the perfusion fluid combined with previous depletion of the intracellular pools); gluconeogenesis was also poorly dependent on the lactate to pyruvate rations in the range of 0.1 to 100; only for a ratio equal to 0.01 was a significantly smaller gluconeogenic activity observed in comparison to the other rations. b) In the presence of Ca2+, the increase in oxygen uptake caused by the infusion of lactate plus pyruvate at a ratio equal to 10 was the most pronounced one; in Ca2+-free perfusion the increase in oxygen uptake caused by lactate plus pyruvate infusion tended to be higher for all lactate to pyruvate ratios; the most pronounced difference was observed for a lactate/pyruvate ratio equal to 1.c) In the presence of Ca2+ the effects of glucagon on gluconeogenesis showed a positive correlation with the lactate to pyruvate rations; for a ratio equal to 0.01 no stimulation ocurred, but in the 0.1 to 100 range stimulation increased progressively, producing a clear parabolic dependence between the effects of glucagon and the lactate to pyruvate ratio. d) In the absence of Ca2+ the relationship between the changes caused by glucagon in gluconeogenesis and the lactate to pyruvate ratio was substantially changed; the dependence curve was no longer parabolic but sigmoidal in shape with a plateau beginning at a lactate/pyruvate ratio equal to 1; there was inhibition at the lactate to pyruvate ratios of 0.01 and 0.1 and a constant stimulation starting with a ratio equal to 1; for the lactate to pyruvate ratios of 10 and 100, stimulation caused by glucagon was much smaller than that found when Ca2+ was present. e) The effects of glucagon on oxygen uptake in the presence of Ca2+ showed a parabolic relationship with the lactate to pyruvate ratios which was closely similar to that found in the case of gluconeogenesis.
Asunto(s)
Ratas , Animales , Calcio/fisiología , Citosol , Glucagón/fisiología , Gluconeogénesis/fisiología , Técnicas In Vitro , NAD/fisiología , Oxidación-Reducción , Hígado , PerfusiónRESUMEN
Production, uptake, and metabolic effects of cyclic AMP (cAMP) were measured in the bivascularly perfused rat liver in anterograde and retrograde perfusion. Glucagon, cAMP, N6,2'-O-dibutyryl cAMP and N6-monobutyryl cAMP were infused into the portal vein (anterograde perfusion), the hepatic vein (retrograde perfusion), or the hepatic artery (anterograde and retrograde perfusion) in order to reach different cell populations. The following results were obtained: (1) cAMP release caused by glucagon was directly proportional to the cell spaces that were accessible via the hepatic artery in anterograde and retrograde perfusion; since the metabolic effects of glucagon were not proportional to the accessible cell spaces, this observation also implies a disproportion between cAMP release and metabolic effects of the hormone; (2) when cAMP and N6,2'-O-dibutyryl cAMP were given to all liver cells (e.g. when infused into the portal vein), their metabolic effects were qualitatively and quantitatively the same and qualitatively equal to the effects of glucagon; (3) the changes caused by cAMP were a function of the cell spaces that can be reached via the hepatic artery in anterograde and retrograde perfusion; this behaviour contrasts markedly with that of glucagon, whose metabolic effects were practically independent of the accessible cell spaces; and (4) the effects of N6,2'-O-dibutyryl cAMP and N6-monobutyryl cAMP were independent of the cell spaces that were accessible via the hepatic artery in anterograde and retrograde perfusion; in this respect their behaviour was equal to that of glucagon. It is apparent that exogenously added cAMP mimicked the metabolic effects of glucagon in the liver only when it was supplied to all liver cells. Since glucagon, N6,2'-O-dibutyryl cAMP, and N6-monobutyryl cAMP were able to produce a full response even when given to only 30% of the liver parenchyma, it was concluded that cAMP production under the stimulus of glucagon or in consequence of the metabolic transformation of N6,2'-O-dibutyryl cAMP and N6-monobutyryl cAMP occurs in a compartment to which exogenous cAMP has no access. cAMP generated within this compartment is possibly able to diffuse from cell to cell.
Asunto(s)
AMP Cíclico/metabolismo , AMP Cíclico/farmacología , Hígado/metabolismo , Animales , Bucladesina/análogos & derivados , Bucladesina/farmacología , Glucagón/farmacología , Glucógeno Hepático/metabolismo , Masculino , Perfusión , Ratas , Ratas WistarRESUMEN
The action of cyanide (500 microM), 2,4-dinitrophenol (50 microM) and atractyloside (100 microM) on glycogen catabolism and oxygen uptake was investigated in the bivascularly perfused liver of fed rats. Cyanide, 2,4-dinitrophenol and attractyloside were infused at identical rates into the hepatic artery in either the anterograde or retrograde perfusion. The accessible aqueous cell spaces were determined by means of the multiple-indicator dilution technique. Glucose release, oxygen uptake and glycolysis were measured as metabolic parameters. Oxygen uptake changes per unit cell space caused by atractyloside (inhibition) and 2,4-dinitrophenol (stimulation) were equal in the retrograde perfusion (periportal cells) and the anterograde perfusion (space enriched in perivenous cells); the decreases caused by cyanide were higher in the retrograde perfusion. Glucose release from periportal cells was not increased upon inhibition of oxidative phosphorylation, a phenomenon which was independent of the mechanism of action of the inhibitor. There were nearly identical changes in glycolysis in the periportal and perivenous cells. It was concluded that: (1) oxygen concentration in the perfused rat liver, if maintained above 100 microM, had little influence on the zonation of the respiratory activity; (2) in spite of the lower activities of the key enzymes of glycolysis in the periportal hepatocytes, as assayed under standard conditions, these cells were as effective as the perivenous ones in generating ATP in the cytosol when oxidative phosphorylation was impaired; (3) the key enzymes of glycogenolysis and glycolysis in periportal and perivenous cells responded differently to changes in the energy charge.
Asunto(s)
Atractilósido/farmacología , Cianuros/farmacología , Dinitrofenoles/farmacología , Glucógeno/metabolismo , Hígado/metabolismo , Oxígeno/metabolismo , 2,4-Dinitrofenol , Animales , Glucosa/metabolismo , Glucólisis , Lactatos/metabolismo , Ácido Láctico , Hígado/efectos de los fármacos , Masculino , Oxidación-Reducción , Perfusión , Fosforilación , Piruvatos/metabolismo , Ácido Pirúvico , Ratas , Ratas Wistar , Sacarosa/metabolismo , Agua/metabolismoRESUMEN
The metabolic action of glucagon in the different spaces that can be reached via the hepatic artery in the bivascularly perfused rat liver of fed rats was investigated. When perfusion was performed in the anterograde mode, glucagon (10 mM) was infused either into the portal vein (type 1 experiment) or into the hepatic artery (type 2); in the retrograde mode, the hormone was infused either into the hepatic vein (type 3) or into the hepatic artery (type 4). The aqueous cell spaces were measured by means of the multiple-indicator dilution technique. Glucose release, oxygen uptake and glycolysis (lactate plus pyruvate production) were measured as metabolic parameters. The following results were obtained. (1) The aqueous cell space accessible via the hepatic artery in the type 2 experiment was 0.63 ml/g; in the type 4 experiment this space was 0.18 ml/g (only periportal cells); glucagon up to 10 nM did not affect these cellular spaces nor did it affect the vascular spaces. (2) The effects of glucagon on glucose release, oxygen uptake and glycolysis were practically the same in all types of experiment (1 to 4), i.e., the action of glucagon was not a function of the accessible cell spaces. (3) When the respiratory chain of the liver cells accessible via the hepatic artery in the type 4 experiment was inhibited by cyanide, glucagon still increased oxygen uptake; oxygen uptake stimulation by glucagon was completely blocked only when cyanide was given to all liver cells. (4) Calcium depletion did not affect the action of glucagon on glucose release and oxygen uptake in the type 4 experiment. It was concluded that, in addition to the receptor-elicited response, the action of glucagon can also be propagated by cell-to-cell communication.
Asunto(s)
Glucagón/farmacología , Hígado/citología , Animales , Calcio/metabolismo , Carbenoxolona/farmacología , Comunicación Celular , Cianuros/farmacología , Espacio Extracelular , Glucagón/administración & dosificación , Gluconeogénesis/efectos de los fármacos , Glucosa/metabolismo , Glucógeno/metabolismo , Arteria Hepática , Venas Hepáticas , Lactatos/metabolismo , Masculino , Consumo de Oxígeno , Perfusión , Vena Porta , Ratas , Ratas WistarRESUMEN
1. The non-steroidal anti-inflammatory naproxen inhibited steady-state glycogenolysis stimulation caused by norepinephrine, phenylephrine (alpha 1-agonists) and methotrexate (not receptor mediated) in the isolated perfused rat liver. Stimulation of glycogenolysis caused by these agents is Ca(2+)-dependent. 2. Naproxen did not inhibit glycogenolysis stimulation caused by glucagon. 3. The action of naproxen depended on the extracellular Ca2+ concentration. At 0.25 mM extracellular Ca2+, the norepinephrine stimulated glycogenolysis was inhibited by 60% by 0.5 mM naproxen. At 3.5 mM Ca2+, inhibition was reduced to 25%. The inhibition degree correlated linearly with the extracellular Ca2+ concentration. 4. 45Ca2+ efflux stimulation caused by norepinephrine was not affected by naproxen, indicating that the mobilization of the intracellular Ca2+ pools was not significantly affected by naproxen. The initial increases in glycogenolysis caused by norepinephrine in the absence of extracellular Ca2+ (pre steady-state) were not affected by naproxen. These increases depend on intracellular Ca2+ mobilization. 5. It can be concluded that the action of naproxen is most probably related to the cytosolic Ca2+ concentration which, under steady-state conditions, depends on the extracellular one during the action of Ca(2+)-dependent glycogenolytic agents.
Asunto(s)
Calcio/fisiología , Glucógeno Hepático/metabolismo , Naproxeno/farmacología , Animales , Glucagón/farmacología , Hígado/metabolismo , Masculino , Metotrexato/farmacología , Fenilefrina/farmacología , Ratas , Ratas WistarRESUMEN
The influence of Ca2+ and the possible action of hormone blockers on the activation of glycogenolysis by methotrexate were investigated. Methotrexate was inactive on glycogenolysis and oxygen uptake when the liver, depleted of intracellular Ca2+, was perfused with Ca(2+)-free medium. The action of methotrexate in calcium-depleted hepatocytes could be restored by the addition of extracellular Ca2+. When Ca2+ was absent in the extracellular medium, but the intracellular stores were not depleted, methotrexate produced transient and progressively attenuated increases in glycogenolysis and oxygen uptake. Like many agonists, methotrexate produced transient increases in Ca2+ efflux. The action of methotrexate was not blocked by the antagonists of norepinephrine, phenylephrine, isoproterenol, vasopressin and angiotensin II. It was concluded that methotrexate acts through a Ca(2+)-dependent mechanism, which is similar to that of the Ca(2+)-dependent agonists. This action, however, seems not to be receptor mediated.
Asunto(s)
Calcio/farmacología , Glucógeno/metabolismo , Hígado/efectos de los fármacos , Metotrexato/farmacología , Animales , Calcio/metabolismo , Glucosa/metabolismo , Hígado/metabolismo , Masculino , Norepinefrina/farmacología , Oxígeno/metabolismo , Perfusión , Prazosina/farmacología , Ratas , Ratas Endogámicas , Receptores de Superficie Celular/efectos de los fármacosRESUMEN
The effects of diltiazem on oxygen uptake, glucose release, lactate production and pyruvate production in the perfused liver from fed rats were investigated. Diltiazem inhibits oxygen uptake and glycolysis. Glucose release from endogenous glycogen is increased after cessation of diltiazem infusion. The reversion of the inhibitory effects of diltiazem after cessation of infusion takes place very slowly. The compound also abolishes glucose release activation by norepinephrine, methotrexate and atractyloside. These effects seem to be the consequence of a more general effect of the drug on metabolism. It can be concluded that 0.5 mM diltiazem is highly toxic to the liver and that it should not be considered a specific agent against Ca(2+)-dependent hormones.
Asunto(s)
Diltiazem/toxicidad , Hígado/efectos de los fármacos , Animales , Atractilósido/farmacología , Glucosa/metabolismo , Técnicas In Vitro , Lactatos/metabolismo , Ácido Láctico , Hígado/metabolismo , Masculino , Metotrexato/farmacología , Norepinefrina/farmacología , Consumo de Oxígeno/efectos de los fármacos , Perfusión , Piruvatos/metabolismo , Ácido Pirúvico , Ratas , Ratas EndogámicasRESUMEN
In vitro treatment of mouse peritoneal cells (mixture of adherent and nonadherent cells) with lysophosphatidylcholine (lyso-Pc) in 10% FCS supplemented medium RPMI 1640 results in a greatly enhanced FcR-mediated phagocytic activity of macrophages. This macrophage-activation process requires a serum factor. Fractionation studies with starch block electrophoresis of fetal calf and human sera revealed that alpha 2-globulin fraction contains a serum factor essential for macrophage activation. To identify the serum factor, human serum was precipitated with 50% saturated ammonium sulfate and fractionated on a Sephadex G-100 column. A protein fraction with a lower m.w. than albumin had the capacity to support activation of macrophages. The active serum factor in this protein fraction was analyzed by immunoabsorption by using rabbit antisera against three major proteins of human alpha 2-globulin. This active serum factor was shown to be a vitamin D3-binding protein (group specific component, Gc). By using a monoclonal anti-Gc-absorbed active column fraction of human serum, we observed no enhanced macrophage activation over the results with serum fraction-free cultivation of lyso-Pc-treated peritoneal cells. Cultivation of lyso-Pc-treated peritoneal cells in a medium containing a low concentration of purified human Gc protein (0.1 to 2.6 ng/ml) produced a greatly enhanced phagocytic activity of macrophages. When purified human Gc protein was used in a serum-free medium for stepwise cultivation of lyso-Pc-treated nonadherent cell types, a macrophage-activating factor was efficiently generated. Therefore, it is concluded that the vitamin D3-binding protein is the essential serum factor for the lyso-Pc-primed activation of macrophages.
Asunto(s)
Lisofosfolípidos/fisiología , Activación de Macrófagos , Macrófagos/fisiología , Proteína de Unión a Vitamina D/fisiología , Animales , Femenino , Humanos , Técnicas In Vitro , Ratones , Ratones Endogámicos BALB C , Cavidad Peritoneal/citología , Transducción de SeñalRESUMEN
Effects of methotrexate (MTX) on mitochondrial oxidative metabolism and ion transport were studied. MTX decreases the membrane potential (delta psi) upon energization of the mitochondrial membrane by NAD+-linked substrates and decreases the amplitude and velocity of swelling induced by glutamate and alpha-ketoglutarate. MTX also has an inhibitory effect on the activities of the oxidation enzymes of NAD+-linked substrates without interfering with the oxidation systems of FAD-linked substrates. The effects of MTX could be interpreted as a consequence of a decrease in the ionic conductivity of the mitochondrial inner membrane.
Asunto(s)
Metotrexato/farmacología , Mitocondrias Hepáticas/metabolismo , Animales , Glutamato Deshidrogenasa/metabolismo , Glicerolfosfato Deshidrogenasa/metabolismo , Técnicas In Vitro , Iones/metabolismo , Isocitrato Deshidrogenasa/metabolismo , Complejo Cetoglutarato Deshidrogenasa/metabolismo , Malato Deshidrogenasa/metabolismo , Masculino , Potenciales de la Membrana/efectos de los fármacos , Mitocondrias Hepáticas/efectos de los fármacos , Mitocondrias Hepáticas/enzimología , Dilatación Mitocondrial/efectos de los fármacos , NAD/metabolismo , Oxidación-Reducción , Ratas , Succinato Deshidrogenasa/metabolismoRESUMEN
Effect of methotrexate (MTX) on mitochondrial oxygen uptake, oxidative phosphorylation and on the activity of several enzymes linked to respiratory chain was studied. MTX was able to inhibit state III respiration activated by ADP and to decrease the respiratory coefficient with the substrates alpha-ketoglutarate and glutamate; these effects became pronounced when mitochondria were pre-incubated with MTX for 10 min. No effect was observed on ATPase activity of undamaged or broken mitochondria; the same was true for NADH-oxidase, NADH-dehydrogenase, NADH-cytochrome c reductase, succinate oxidase, and cytochrome c oxidase activity. The effect on the steady-state of cytochrome b, as well as, the inhibitory effect on state III of respiration with NAD+-linked substrates, offers a reasonable possibility to suggesting that the inhibition site of MTX could be in a place anterior to cytochrome b region, and not linked to respiratory chain.
Asunto(s)
Metotrexato/farmacología , Mitocondrias Hepáticas/metabolismo , Fosforilación Oxidativa/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Adenosina Trifosfatasas/metabolismo , Animales , Grupo Citocromo b/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Técnicas In Vitro , Mitocondrias Hepáticas/efectos de los fármacos , Complejos Multienzimáticos/metabolismo , NADH Deshidrogenasa/metabolismo , NADH NADPH Oxidorreductasas/metabolismo , Polarografía , Ratas , Succinato Deshidrogenasa/metabolismoRESUMEN
To obtain direct evidence for the involvement of IgE antibodies in eosinophil-mediated killing of schistosomula of S. japonicum, dinitrophenylated (DNP) schistosomula pretreated with mouse monoclonal IgE antibodies were co-cultured with purified rat peritoneal eosinophils. It was found that the eosinophil-mediated adherence and damage to haptenated schistosomula were dependent on a monoclonal anti-DNP IgE antibody, but not on monoclonal anti-ovalbumin IgE antibody. Moreover, eosinophils from N. brasiliensis-infected rats demonstrated an enhanced ability in the IgE-dependent damage to DNP-schistosomula as compared with the cells from normal rats. The enhancement was associated with an increase in the proportion of eosinophils expressing Fc receptors for IgE.