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1.
Conscious Cogn ; 106: 103420, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36274390

RESUMEN

The current study demonstrates the abolishment of the Ownership Self Reference Effect (OSRE) when elaborate details of a distant other-referent are provided. In a 2 (High versus Low information) × 2 (Self versus Other) experimental design, we tested the capacity for the SRE to be modulated with social saliency. Using a well-established ownership paradigm (Collard et al., 2020; Cunningham et al., 2008; Sparks et al., 2016), when the other was made socially salient (i.e. details and characteristics about the other were provided to the participant prior to encoding), no SRE emerged, such that self-owned and other-owned items were recalled with comparable accuracy. In contrast, when the other was not salient (i.e., no details about them were provided), participants accurately recalled a higher proportion of self-owned items, demonstrating a typical SRE in source memory. The degree of self- or other- referencing was not related to measured variables of closeness, similarity or shared traits with the other. Although the SRE is an established and robust effect, the findings of the current study illustrate critical circumstances in which the self is no longer prioritised above the other. In line with our predictions, we suggest that the self has automatic attributed social salience (e.g. through ownership) and that enhancing social salience by elaborating details of the other, prioritisation can expand to encapsulate an other beyond the self and influence incidental memory.


Asunto(s)
Recuerdo Mental , Propiedad , Humanos , Autoimagen
2.
Climacteric ; 25(4): 369-375, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-34694941

RESUMEN

OBJECTIVE: The aim of this study is to analyze the association between coronary artery vitamin D receptor (VDR) expression and systemic coronary artery atherosclerosis (CAA) risk factors. METHODS: Female cynomolgus monkeys (n = 39) consumed atherogenic diets containing the women's equivalent of 1000 IU/day of vitamin D3. After 32 months consuming the diets, each monkey underwent surgical menopause. After 32 postmenopausal months, CAA and VDR expression were quantified in the left anterior descending coronary artery. Plasma 25OHD3, lipid profiles and serum monocyte chemotactic protein-1 (MCP-1) were measured. RESULTS: In postmenopausal monkeys receiving atherogenic diets, serum MCP-1 was significantly elevated compared with baseline (482.2 ± 174.2 pg/ml vs. 349.1 ± 163.2 pg/ml, respectively; p < 0.001; d = 0.79) and at the start of menopause (363.4 ± 117.2 pg/ml; p < 0.001; d = 0.80). Coronary VDR expression was inversely correlated with serum MCP-1 (p = 0.042). Additionally, the change of postmenopausal MCP-1 (from baseline to necropsy) was significantly reduced in the group with higher, compared to below the median, VDR expression (p = 0.038). The combination of plasma 25OHD3 and total plasma cholesterol/high-density lipoprotein cholesterol was subsequently broken into low-risk, moderate-risk and high-risk groups; as the risk increased, the VDR quantity decreased (p = 0.04). CAA was not associated with various atherogenic diets. CONCLUSION: Coronary artery VDR expression was inversely correlated with markers of CAA risk and inflammation, including MCP-1, suggesting that systemic and perhaps local inflammation in the artery may be associated with reduced arterial VDR expression.


Asunto(s)
Aterosclerosis , Enfermedad de la Arteria Coronaria , Receptores de Calcitriol/metabolismo , Aterosclerosis/complicaciones , Enfermedad de la Arteria Coronaria/etiología , Femenino , Humanos , Inflamación , Factores de Riesgo , Vitamina D
3.
Nutr Metab Cardiovasc Dis ; 24(4): 423-7, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24525253

RESUMEN

BACKGROUND AND AIMS: To examine effects of equol, the soy phytoestrogen metabolite, on gene expression in the monkey iliac artery. METHODS AND RESULTS: A high fat/high cholesterol diet was fed to eight ovariectomized cynomolgus monkeys for 6.5 years. After biopsy of the left iliac artery, the animals were randomized to two treatment groups for 8 months; the treatment groups were equol (23.7 mg/100 g diet, n = 4) and vehicle (n = 4). The right iliac artery was removed at necropsy. Gene expression in the iliac arteries in response to equol was determined by DNA microarray. Comparison of atherosclerotic lesions and plasma lipids at pre-versus post-equol treatment time points and in vehicle versus equol treatment groups did not identify any significant differences. Despite the lack of effect of equol on these parameters, 59 genes were down-regulated and 279 were up-regulated in response to equol. Comparison of these data to previous work identified 10 genes regulated in opposite directions by equol compared to presence of atherosclerosis plaque (Menopause 2011; 18:1087-1095) and 55 genes differentially expressed in the same direction in response to both equol and estradiol (Eyster et al., Menopause 2014;21:143-152.). CONCLUSIONS: Similar responses of genes to both equol and estradiol may reflect the extent to which equol serves as a natural selective estrogen receptor modulator in the arteries. Opposite responses of 10 genes to equol versus the presence of atherosclerosis implicates those genes in the potential protective effects of equol in arteries.


Asunto(s)
Aterosclerosis/tratamiento farmacológico , Equol/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Arteria Ilíaca/efectos de los fármacos , Fitoestrógenos/farmacología , Animales , Aterosclerosis/genética , Aterosclerosis/metabolismo , Aterosclerosis/patología , Dieta Alta en Grasa , Modelos Animales de Enfermedad , Femenino , Arteria Ilíaca/metabolismo , Arteria Ilíaca/patología , Macaca fascicularis , Ovariectomía , Placa Aterosclerótica , Factores de Tiempo
4.
Biol Psychol ; 179: 108564, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-37061084

RESUMEN

Elevated irritability during adolescence predicts mental health issues in adulthood. Social interactions commonly elicit symptoms of irritability. Prior research has traditionally examined neural activity during the anticipation of, and immediate reaction to, social feedback separately in irritable adolescents. However, studies suggest that irritable adolescents demonstrate altered brain activation when anticipating feedback, and these alterations may have downstream effects on the neural activity when actually presented with feedback. Thus, the goal of this study was to characterize the influence of irritability on the relationship between brain function during anticipation and receipt of social feedback. We leveraged the Virtual School task to mimic social interactions using dynamic stimuli. Parallel region of interest (ROI) analyses tested effects of anticipatory bilateral amygdala (or dorsal anterior cingulate cortex; dACC) activation on the dACC (or bilateral amygdala) activation during receipt of peer feedback. Parallel exploratory whole-brain analyses were conducted to identify the effects of anticipatory bilateral amygdala or dACC activation on other regions during receipt of peer feedback. In ROI analyses, more vs. less irritable adolescents showed distinct relationships between anticipatory bilateral amygdala activation and dACC activation when receiving predictably mean feedback. Across both whole-brain analyses, anticipatory bilateral amygdala and dACC activation were separately associated with activation in socioemotional regions of the brain during subsequent feedback. These relationships were modulated by irritability, and the valence and predictability of the feedback. This suggests that irritable adolescents may engage in altered emotion processing and regulation strategies, depending on the valence and predictability of social feedback.


Asunto(s)
Encéfalo , Genio Irritable , Humanos , Adolescente , Retroalimentación , Genio Irritable/fisiología , Giro del Cíngulo/fisiología , Grupo Paritario , Imagen por Resonancia Magnética
5.
Hum Reprod ; 25(12): 3083-94, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20956266

RESUMEN

BACKGROUND: Psychological stress may impair premenopausal ovarian function and contribute to risk for chronic disease. Soy isoflavones may also influence ovarian function and affect health. Here, we report the effects of a psychological stressor (subordinate social status) and dietary soy on reproductive function and related health indices in female monkeys. We hypothesized that reproductive compromise and adverse health outcomes would be induced in subordinate when compared with dominant monkeys and be mitigated by exposure to soy. METHODS: Subjects were 95 adult cynomolgus monkeys (Macaca fascicularis) housed in social groups of five or six. Animals consumed a soy-free, animal protein-based diet during an 8-month Baseline phase and then, during a 32-month Treatment phase, consumed either the baseline diet or an identical diet that substituted high-isoflavone soy protein for animal protein. RESULTS: Across more than 1200 menstrual cycles, subordinate monkeys consistently exhibited ovarian impairment [increased cycle length (P < 0.02) and variability (P < 0.02) and reduced levels of progesterone (P < 0.04) and estradiol (P < 0.04)]. Subordinate status was confirmed behaviorally and was associated with elevated cortisol (P < 0.04) and relative osteopenia (P < 0.05). Consumption of the soy diet had no significant effects. CONCLUSIONS: (i) Psychological stress adversely affects ovarian function and related health indices in a well-accepted animal model of women's health; (ii) Similar effects may extend to women experiencing reproductive impairment of psychogenic origin; (iii) soy protein and isoflavones neither exacerbate nor mitigate the effects of an adverse psychosocial environment; and (iv) this study was limited by an inability to investigate the genetic and developmental determinants of social status.


Asunto(s)
Dieta , Jerarquia Social , Isoflavonas/administración & dosificación , Proteínas de Soja/administración & dosificación , Estrés Psicológico/complicaciones , Animales , Anovulación/etiología , Densidad Ósea , Enfermedades Óseas Metabólicas/psicología , Dexametasona , Proteínas en la Dieta/administración & dosificación , Estradiol/sangre , Femenino , Hidrocortisona/sangre , Macaca fascicularis , Trastornos de la Menstruación/etiología , Premenopausia , Progesterona/sangre
6.
Neurotoxicology ; 81: 282-287, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-35587135

RESUMEN

Large numbers of individuals suffered severe neurological effects from poisoning with methyl mercury from the consumption of fish contaminated by industrial discharge in Minamata in the 1950s and 1960s and from bread made from fungicide-treated wheat in the early 1970s in Iraq. In both episodes, infants exposed in utero showed developmental delays. Data from Iraq permitted the estimation of dose-response relationships and provided evidence of greater sensitivity of the foetal brain compared to adult. Studies in a number of communities regularly consuming fish have sought to determine whether and at what level of prenatal exposure neurodevelopment defects may be detected, but the findings do not present a consistent picture. Benchmark analysis using data from Iraq and the three largest studies (New Zealand, Faroes, and Seychelles) suggest an overlap in estimated dose corresponding to a 10% increase in prevalence of adverse effects above background level. However, the Seychelles study, examining children up to 9 years of age, has not found a consistent pattern of adverse developmental effects; a possible explanation may be the presence of micronutrients in the ocean fish diet that enhance brain development and/or counter the toxic effects of methyl mercury.


Asunto(s)
Mercurio , Compuestos de Metilmercurio , Efectos Tardíos de la Exposición Prenatal , Animales , Dieta , Femenino , Peces , Contaminación de Alimentos/análisis , Humanos , Mercurio/análisis , Compuestos de Metilmercurio/análisis , Compuestos de Metilmercurio/toxicidad , Nueva Zelanda , Embarazo , Efectos Tardíos de la Exposición Prenatal/inducido químicamente , Seychelles/epidemiología
7.
Science ; 216(4541): 61-3, 1982 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-7063871

RESUMEN

The long half-time for methylmercury in the neonatal rats is explained by the neonatal liver's inability to secrete the toxin into bile, which in adults is the main route of elimination. The ability to secrete mercury into bile develops between 2 and 4 weeks of age and is correlated with the increasing ability of the developing liver to secrete glutathione into bile.


Asunto(s)
Bilis/metabolismo , Glutatión/metabolismo , Hígado/metabolismo , Compuestos de Metilmercurio/metabolismo , Factores de Edad , Animales , Transporte Biológico , Hígado/crecimiento & desarrollo , Ratas , Compuestos de Sulfhidrilo/metabolismo
8.
Science ; 201(4355): 538-41, 1978 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-96532

RESUMEN

Diet-induced atherosclerosis developed more extensively in vasectomized cynomolgus monkeys (Macaca fascicularis) than in sham-vasectomized control monkeys fed the same diet. The effect was most pronounced in the abdominal aortas, carotid arteries, distal segments of the coronary arteries, and intracranial cerebral arteries. Antibodies to sperm developed in all vasectomized monkeys, and complement and immunoglobulins were associated with atherosclerotic plaques in some of the vasectomized animals. The immunological response to sperm antigens that often accompanies vasectomy may exacerbate atherosclerosis.


Asunto(s)
Arteriosclerosis/etiología , Vasectomía/efectos adversos , Animales , Arterias/inmunología , Arterias/patología , Arteriosclerosis/inmunología , Arteriosclerosis/patología , Autoanticuerpos , Colesterol/metabolismo , Ésteres del Colesterol/metabolismo , Dieta Aterogénica , Haplorrinos , Macaca fascicularis , Masculino , Espermatozoides/inmunología
9.
Science ; 213(4512): 1123-5, 1981 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-7268418

RESUMEN

Volatile mercury was produced de novo by mouse tissue homogenates that contained mercuric ions. Ethanol stimulated the release of tissue mercury into the vapor phase, and the mechanism appears to be an inhibition of reoxidation of volatile mercury. Components responsible for mercury volatilization are heat-labile. The highest volatilizing activity in the liver is associated with the soluble fraction obtained after centrifugation at 105,000g.


Asunto(s)
Etanol/farmacología , Inactivación Metabólica , Riñón/metabolismo , Hígado/metabolismo , Mercurio/metabolismo , Animales , Compartimento Celular , Sistema Libre de Células , Cisteína , Gases , Ratones , Oxidación-Reducción
10.
Science ; 227(4687): 638-40, 1985 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-2857500

RESUMEN

Phenylmercury absorbed through the skin from contaminated diapers affected urinary excretion in infants in Buenos Aires. The effects were reversible and quantitatively related to the concentration of urinary mercury. Excretion of gamma-glutamyl transpeptidase, an enzyme in the brush borders of renal tubular cells, increased in a dose-dependent manner when mercury excretion exceeded a "threshold" value. Urine volume also increased but at a higher threshold with respect to mercury. The results support the threshold concept of the systemic toxicity of metals. gamma-Glutamyl transpeptidase is a useful and sensitive marker for preclinical effects of toxic metals.


Asunto(s)
Fungicidas Industriales/farmacología , Compuestos de Fenilmercurio/farmacología , Adulto , Animales , Argentina , Creatinina/orina , Relación Dosis-Respuesta a Droga , Humanos , Lactante , Mercurio/orina , Intoxicación por Mercurio/etiología , Proteinuria/metabolismo , Urodinámica/efectos de los fármacos , gamma-Glutamiltransferasa/orina
11.
Science ; 220(4598): 733-5, 1983 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-6836311

RESUMEN

Socially stressed adult male cynomolgus monkeys (Macaca fascicularis) fed a low fat, low cholesterol diet developed more extensive coronary artery atherosclerosis than unstressed controls. Groups did not differ in serum lipids, blood pressure, serum glucose, or ponderosity. These results suggest that psychosocial factors may influence atherogenesis in the absence of elevated serum lipids. Psychosocial factors thus may help explain the presence of coronary artery disease (occasionally severe) in people with low or normal serum lipids and normal values for the other "traditional" risk factors.


Asunto(s)
Arteriosclerosis/etiología , Estrés Psicológico/complicaciones , Animales , Arteriosclerosis/patología , Presión Sanguínea , Colesterol/sangre , Vasos Coronarios/patología , Estructura de Grupo , Humanos , Macaca fascicularis , Masculino , Medio Social
12.
Artículo en Inglés | MEDLINE | ID: mdl-18585023

RESUMEN

Information on the status of long-chain polyunsaturated fatty acids (LCPUFAs) in pregnancy and breast milk in very high fish-eating populations is limited. The aim of this study was to examine dietary intake and changes in fatty acid status in a population of pregnant women in the Republic of Seychelles. Serum docosahexaenoic acid (DHA) decreased significantly between 28-week gestation and delivery (n=196). DHA status did not correlate significantly with length of gestation and was not associated with self-reported fish intake, which was high at 527 g/week. In breast milk, the ratio of DHA to arachidonic acid (AA) was consistent with those observed in other high fish-eating populations. Overall the data suggest that high exposure to LCPUFAs from habitual fish consumption does not prevent the documented decrease in LCPUFA status in pregnancy that occurs as a result of foetal accretion in the third trimester of pregnancy.


Asunto(s)
Ingestión de Energía/fisiología , Ácidos Grasos Insaturados/metabolismo , Peces , Alimentos Marinos/análisis , Adulto , Animales , Desarrollo Infantil/fisiología , Dieta , Ácidos Docosahexaenoicos/análisis , Ácidos Docosahexaenoicos/sangre , Ácidos Eicosanoicos/análisis , Ácidos Eicosanoicos/sangre , Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/sangre , Femenino , Edad Gestacional , Humanos , Recién Nacido , Leche Humana/química , Leche Humana/metabolismo , Fenómenos Fisiológicos de la Nutrición , Periodo Posparto/sangre , Periodo Posparto/metabolismo , Embarazo , Tercer Trimestre del Embarazo/sangre , Tercer Trimestre del Embarazo/metabolismo , Seychelles
13.
Climacteric ; 11(5): 409-15, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18781486

RESUMEN

OBJECTIVES: Tibolone is often taken concurrently with soy. Tibolone, soy and equol-producing capacity each affect vascular health, whereas their concomitant effects are unknown. We studied the effects of soy on sex steroids and vascular inflammation markers in long-term tibolone users. METHODS: Postmenopausal women (n = 110) on tibolone were screened with a soy challenge to find 20 equol producers and 20 non-producers. All women were treated for 8 weeks in a cross-over trial with soy (52 g of soy protein containing 112 mg of isoflavones) or placebo. Serum estrone, 17beta-estradiol, testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS), sex hormone binding globulin (SHBG), C-reactive protein (CRP), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and platelet-selectin (P-selectin) were assessed. RESULTS: Soy decreased (7.1%) the estrone level, significantly (12.5%) only in equol producers (from 80.2 +/- 10.8 to 70.3 +/- 7.0 pmol/l; p = 0.04). Testosterone was reduced (15.5%; from 586 +/- 62.6 to 495 +/- 50.1 pmol/l, p = 0.02) during soy treatment, and more markedly in equol producers than non-producers (22.1% vs. 10.0%). No changes appeared in SHBG, CRP or ICAM-1, but VCAM-1 increased (9.2%) and P-selectin decreased (10.3%) during soy treatment. CONCLUSIONS: Soy modified the concentrations of estrone, testosterone and some endothelial markers. Equol production enforced these effects. Soy supplementation may be clinically significant in tibolone users.


Asunto(s)
Moduladores de los Receptores de Estrógeno/uso terapéutico , Isoflavonas/metabolismo , Norpregnenos/uso terapéutico , Posmenopausia , Proteínas de Soja/administración & dosificación , Proteína C-Reactiva/análisis , Estudios Cruzados , Equol , Estrona/sangre , Femenino , Humanos , Molécula 1 de Adhesión Intercelular/sangre , Persona de Mediana Edad , Selectina-P/sangre , Globulina de Unión a Hormona Sexual/análisis , Testosterona/sangre , Molécula 1 de Adhesión Celular Vascular/sangre
14.
J Clin Invest ; 65(1): 15-25, 1980 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-6765957

RESUMEN

We demonstrated previously that atherosclerosis develops more extensively in vasectomized cynomolgus macaques fed an atherogenic diet and speculated that the immunologic response to sperm antigens may have exacerbated the atherosclerosis. We report here that rhesus monkeys vasectomized for 9-14 yr and fed monkey chow (devoid of cholesterol and low in fat) rather than an atherogenic diet also had more extensive and severe atherosclerosis than did control animals of the same age. The extent of atherosclerosis was considered as the percentage of intimal surface with plaques. No control animals were found to have plaques in the thoracic aorta, but 7 of 10 vasectomized monkeys were affected. The plaques in the vasectomized monkeys occupied about 13% of the intimal surface. In 4 of 7 control monkeys and 7 of 10 vasectomized monkeys there were lesions in the abdominal aortas; the lesions were considerably more extensive and severe in the vasectomized animals. Lesions were also more common in iliac arteries of vasectomized animals, and the extent was increased about threefold. Plaques were seen at the carotid bifurcation in all of the animals of both the control and vasectomized groups. The carotid bifurcation plaques of the vasectomized monkeys were larger than those of the control animals on the right but not on the left side. Histologically, the lesions of vasectomized monkeys did not appear to be qualitatively different from those of control animals, even though they were larger and contained more collagen, lipid, and mucopolysaccharides. Grossly, the distribution of the lesions in the vasectomized animals was different from that in the control animals, and that of lesions induced by atherogenic diets, i.e., the lesions were distributed randomly within the artery rather than around bifurcations. More extensive atherosclerosis was noted among vasectomized animals that were found to lack demonstrable circulating free antisperm antibodies. On the basis of the observations made in this study, we suggest that the antisperm antibodies that form after vasectomy may result in circulating immune complexes that exacerbate atherosclerosis.


Asunto(s)
Arteriosclerosis/etiología , Vasectomía/efectos adversos , Animales , Formación de Anticuerpos , Complejo Antígeno-Anticuerpo , Enfermedades de la Aorta/patología , Arteriosclerosis/patología , Enfermedades de las Arterias Carótidas/patología , Grasas de la Dieta/administración & dosificación , Haplorrinos , Arteria Ilíaca , Macaca mulatta , Masculino , Espermatozoides/inmunología , Factores de Tiempo
15.
J Clin Invest ; 88(6): 1995-2002, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1752958

RESUMEN

The effect of estrogen and progesterone replacement therapy on the initiating events in atherogenesis was studied in surgically postmenopausal cynomolgus monkeys. Monkeys were ovariectomized and divided randomly into two groups, one receiving 17 beta-estradiol and cyclic progesterone treatment (n = 9) and ovariectomized controls receiving no hormone replacement therapy (n = 8). The monkeys were fed a moderately atherogenic diet for 18 wk to accelerate the early pathogenic processes but not to be of sufficient duration to produce grossly visible atherosclerotic lesions. Sex hormone replacement therapy decreased the accumulation of LDL and products of LDL degradation in the coronary arteries by greater than 70% while having no significant effect on plasma lipid, lipoprotein, or apoprotein concentrations. Arterial intimal lesions were small with no difference between groups. The reduction in arterial LDL metabolism occurred very early in the pathogenesis of atherosclerosis and was independent of indices of endothelial cell injury, such as enhanced endothelial cell turnover or leukocyte adhesion to the endothelium. Results of this study suggest that one mechanism by which sex hormone treatment inhibits the initiation of atherosclerosis is a direct effect at the level of the arterial wall by suppressing the uptake and/or degradation of LDL.


Asunto(s)
Arteriosclerosis/etiología , Vasos Coronarios/metabolismo , Terapia de Reemplazo de Estrógeno , Estrógenos/uso terapéutico , Lipoproteínas LDL/metabolismo , Menopausia/metabolismo , Progesterona/uso terapéutico , Animales , Celobiosa/metabolismo , Vasos Coronarios/patología , Vasos Coronarios/ultraestructura , Femenino , Macaca fascicularis , Ovariectomía
16.
Neurotoxicology ; 28(5): 1015-22, 2007 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-17382399

RESUMEN

Several biological media have been used as indicators of the fetal body burden of methylmercury and the levels in the primary target tissue, the developing brain. These media include maternal hair and blood. The relative merits of these media will be considered both with regard to current knowledge of the physiology of mercury disposition in the body and also the practicality of field application with respect to sample, collection, transport, storage and processing.


Asunto(s)
Monitoreo del Ambiente , Compuestos de Metilmercurio/análisis , Adulto , Femenino , Cabello/química , Humanos , Indicadores y Reactivos , Compuestos de Metilmercurio/sangre , Compuestos de Metilmercurio/farmacocinética , Embarazo
17.
Biochim Biophys Acta ; 523(2): 522-31, 1978 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-656439

RESUMEN

The formation of glutathione radicals, the evolution of nascent oxygen or the peroxidatic reaction with catalase complex I are considered as possible mechanisms for the oxidation of mercury vapor by red blood cells. To select among these, the uptake of atomic mercury by erythrocytes from different species was studied and related to their various activities of catalase (hydrogenperoxide : hydrogen-peroxide oxidoreductase, EC 1.11.1.6) and glutathione peroxidase (glutathione : hydrogen-peroxide oxidoreductase, EC 1.11.1.9). A slow and continuous infusion of diluted H2O2 was used to maintain steady concentrations of complex I. 1% red cell supsensions were found most suitable showing high rates of Hg uptake and yielding still enough cells for subsequent determinations. The results indicate that the oxidation of mercury depends upon the H2O2-generation rate and upon the specific acticity of red-cell catalase. The oxidation occurred in a range of the catalase-H2O2 reaction where the evolution of oxygen could be excluded. Compounds reacting with complex I were shown to be effective inhibitors of the mercury uptake. GSH-peroxidase did not participate in the oxidation but rather, was found to inhibit it by competing with catalase for hydrogen peroxide. These findings support the view that elemental mercury is oxidized in erythrocytes by a peroxidatic reaction with complex I only.


Asunto(s)
Eritrocitos/metabolismo , Mercurio/sangre , Animales , Transporte Biológico , Catalasa/sangre , Patos , Glutatión Peroxidasa/sangre , Hemoglobinas/metabolismo , Humanos , Cinética , Ratones , Oxígeno/sangre , Especificidad de la Especie
18.
Biochim Biophys Acta ; 991(1): 85-9, 1989 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-2713425

RESUMEN

The lung plays a major role in the removal of dissolved elemental mercury (Hg0) from the bloodstream. During the first passage through the lung after an intravenous dose of Hg0 dissolved in aqueous buffer, from 10 to 17% was exhaled depending on the dose (0.11 or 1.1 micrograms Hg/rat) and the injection site (jugular versus tail vein). Furthermore, evidence is presented that subsequent exhalation over the next 50 s, before the rats were killed and the mercury determined in the lung at that time, was largely Hg0-extracted during the first pass. The total mercury extracted during the 60 s period was in the range of 40-49% of the dose. The oxidation of Hg0 to Hg2+ in red cells is important in limiting the availability of Hg0 to certain tissues. Thus, after a short residence time in blood (0.6 s after jugular vein injection), 12.9-17% is exhaled in the first pass as compared to 10.4-12.2% with a longer residence time (1.8 s after tail vein injection). Furthermore, there was a general tendency, even at 60 s after dosing, for certain tissues - lung, brain, and heart - to have higher values after dosing from the jugular vein. It was estimated that the half-time for oxidation was 3.3 s. Our results confirm previous observations that the form of inorganic mercury greatly influences the short-term deposition in certain tissues. Thus as compared to Hg2+, administration of Hg0 increases lung levels 5-10-fold; brain, 4-fold; and heart, 3-fold. Blood levels are lower after Hg0, particularly after the higher dose. Such findings are consistent with a model wherein Hg0 is in part oxidized by red blood cells, the remainder rapidly diffusing in tissues where it is also oxidized to Hg2+.


Asunto(s)
Pulmón/fisiología , Mercurio/farmacocinética , Animales , Pruebas Respiratorias , Cationes , Relación Dosis-Respuesta a Droga , Inyecciones Intravenosas , Venas Yugulares , Pulmón/análisis , Masculino , Mercurio/administración & dosificación , Mercurio/sangre , Oxidación-Reducción , Circulación Pulmonar , Ratas , Ratas Endogámicas , Cola (estructura animal)/irrigación sanguínea , Factores de Tiempo , Distribución Tisular , Relación Ventilacion-Perfusión
19.
Diabetes ; 31(Suppl 1 Pt 2): 54-64, 1982.
Artículo en Inglés | MEDLINE | ID: mdl-7160535

RESUMEN

This report summarizes the current state of knowledge concerning the cardiovascular system in various animal models of diabetes and presents their major strengths and weaknesses for studying the important research questions in the field. Nonhuman primates have many desirable features for studies on the macrovascular and cardiac complications of the disease as well as risk factor alterations, but their availability, cost, and maintenance present practical disadvantages. The spontaneous rodent models of diabetes currently are not considered very useful for cardiovascular research, but they have not been well characterized with respect to most aspects of their cardiovascular system. Alloxan-diabetic rabbits offer some promise for examining the effects of diabetes on atherogenesis, lipoprotein metabolism, and cardiomyopathy, but additional research is required to validate their usefulness. Insufficient data are available on canine and swine models of diabetes to judge their merits for cardiovascular research. The Task Force recommends: (1) additional longterm investigations to determine the extent and severity of cardiovascular complications in the well-characterized rodent models and in diabetic rodents with multiple risk factor abnormalities; (2) further studies on the macrovascular disease and lipoprotein abnormalities of the alloxan-diabetic rabbit and the development of rabbit colonies with spontaneous diabetes; (3) increased emphasis on such potentially important but neglected areas of research in diabetic animals as the intramyocardial circulation, adventitial blood vessels, blood pressure, platelet function, blood coagulation, blood rheology, and autonomic nervous function; (4) long-term studies on the influence of control of hyperglycemia and of insulin therapy on cardiovascular complications in diabetic animals; and (5) encouragement of use of diabetic nonhuman primates for cardiovascular research and institution of measures to increase their supply and availability by expanding current colonies, screening newly imported animals for diabetes, and establishing a visiting scientist's program allowing investigators to study diabetic primates at resource centers.


Asunto(s)
Enfermedades Cardiovasculares/etiología , Angiopatías Diabéticas , Modelos Animales de Enfermedad , Animales , Arteriosclerosis/etiología , Cardiomiopatías/etiología , Cricetinae , Cricetulus , Perros , Hipercolesterolemia/etiología , Lipoproteínas/sangre , Macaca , Macaca fascicularis , Macaca mulatta , Ratones , Ratones Obesos , Conejos , Ratas , Ratas Endogámicas , Ratas Zucker , Saimiri , Porcinos
20.
J Gen Physiol ; 50(3): 695-727, 1967 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11526854

RESUMEN

The flows of sodium, potassium, and chloride under electrical and chemical gradients and of salt and water in the presence of osmotic pressure gradients are described by phenomenological equations based on the thermodynamics of irreversible processes. The aim was to give the simplest possible description, that is to postulate the least number of active transport processes and the least number of separate pathways across the intestine. On this basis, the results were consistent with the following picture of the intestine: Two channels exist across this tissue, one allowing only passive transport of ions and the other only active. In the passive channel, the predominant resistance to ion flow is friction with the water in the channel. The electroosmotic flow indicates that the passive channel is lined with negative fixed charged groups having a surface charge density of 3000 esu cm-2. The values of the ion-water frictional coefficients, and the relationship between ionic concentrations and flows indicate that the passive channel is extracellular. The active channel behaves as two membranes in series, the first membrane being semipermeable but allowing active transport of sodium, and the second membrane being similar to the passive channel. Friction with the ions in the second "membrane" is the predominant resistance to water flow.


Asunto(s)
Íleon/metabolismo , Sales (Química)/farmacocinética , Agua/metabolismo , Animales , Transporte Biológico Activo/fisiología , Cloruros/farmacocinética , Estimulación Eléctrica , Absorción Intestinal/fisiología , Mucosa Intestinal/metabolismo , Modelos Biológicos , Ósmosis/fisiología , Presión Osmótica , Potasio/farmacocinética , Ratas , Sodio/farmacocinética
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