RESUMO
In order to address the present difficulty in experimentally generating the relativistic Laguerre-Gaussian laser, primarily due to damage caused to optical modulators, a high-reflectivity phase mirror is applied in the femtosecond petawatt laser system to generate a relativistic hollow laser at the highest intensity of 6.3×10^{19} W/cm^{2} for the first time. A simple optical model is used to verify that the vortex laser may be generated in this new scheme; using such a relativistic vortex laser, the hollow plasma drill and acceleration are achieved experimentally and proven by particle-in-cell simulations. With the development of the petawatt laser, this scheme opens up possibilities for the convenient production of the relativistic hollow laser at high repetition and possible hollow plasma acceleration, which is important for a wide range of applications such as the generation of radiation sources with orbital angular momentum, fast ignition for inertial confinement fusion, and jet research in the astrophysical environment.
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We present experimental studies on ion acceleration using an 800-nm circularly polarized laser pulse with a peak intensity of 6.9×10^{19} W/cm^{2} interacting with an overdense plasma that is produced by a laser prepulse ionizing an initially ultrathin plastic foil. The proton spectra exhibit spectral peaks at energies up to 9 MeV with energy spreads of 30% and fluxes as high as 3×10^{12} protons/MeV/sr. Two-dimensional particle-in-cell simulations reveal that collisionless shocks are efficiently launched by circularly polarized lasers in exploded plasmas, resulting in the acceleration of quasimonoenergetic proton beams. Furthermore, this scheme predicts the generation of quasimonoenergetic proton beams with peak energies of approximately 150 MeV using current laser technology, representing a significant step toward applications such as proton therapy.
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Emergent phenomena at polar-nonpolar oxide interfaces have been studied intensely in pursuit of next-generation oxide electronics and spintronics. Here we report the disentanglement of critical thicknesses for electron reconstruction and the emergence of ferromagnetism in polar-mismatched LaMnO_{3}/SrTiO_{3} (001) heterostructures. Using a combination of element-specific x-ray absorption spectroscopy and dichroism, and first-principles calculations, interfacial electron accumulation, and ferromagnetism have been observed within the polar, antiferromagnetic insulator LaMnO_{3}. Our results show that the critical thickness for the onset of electron accumulation is as thin as 2 unit cells (UC), significantly thinner than the observed critical thickness for ferromagnetism of 5 UC. The absence of ferromagnetism below 5 UC is likely induced by electron overaccumulation. In turn, by controlling the doping of the LaMnO_{3}, we are able to neutralize the excessive electrons from the polar mismatch in ultrathin LaMnO_{3} films and thus enable ferromagnetism in films as thin as 3 UC, extending the limits of our ability to synthesize and tailor emergent phenomena at interfaces and demonstrating manipulation of the electronic and magnetic structures of materials at the shortest length scales.
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Enalapril maleate (EM) is unstable in poorly designed tablet formulations. To improve the stability of EM, the degradation mechanism should be elucidated. In this study, we found that several commonly used excipients promoted the degradants of EM, particularly a diketopiperazine derivative (DKP). We propose two degradation pathways in which both acid and alkali can promote the formation of DKP, although previous reports suggested that DKP is produced mainly in acidic media. Based on the degradation pathways, we believe that subtle control of the microenvironmental pH can inhibit the formation of DKP. This was confirmed by the observation that the degradation rate became slower when certain organic acids were added to the binary mixtures of EM and excipient. The data showed that the stability of EM in the ternary mixtures was much higher than that in binary mixtures. It was further proved that tablets containing these organic acids produced less DKP after the accelerated test. We also found that the formation of DKP in tablets varied with different ratios of tartaric acid, which was used as a model organic acid. This illustrated that an optimum ratio of tartaric acid is required. These results indicated that the stability of EM in tablet formulation is closely associated with microenvironmental pH and the addition of a suitable organic acid based on the reaction mechanism is an effective strategy for improving the stability of EM.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/química , Enalapril/química , Inibidores da Enzima Conversora de Angiotensina/análise , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , Contaminação de Medicamentos , Incompatibilidade de Medicamentos , Enalapril/análise , Excipientes , Cinética , Espectrometria de Massas , ComprimidosRESUMO
OBJECTIVE: To evaluate the feasibility of determining the target vertebral body (TV) of uncompressed elderly osteoporotic thoracolumbar fractures through measuring Hounsfield unit (HU) value. PATIENTS AND METHODS: Elderly patients with osteoporotic thoracolumbar fractures aged above 65 years old hospitalized from 2015 to 2016 were retrospectively analyzed. The cases whose TV could not be determined by computed tomography (CT) imaging but confirmed by magnetic resonance imaging (MRI) were selected. The mean HU values of the trabecular bone regions of TV and adjacent vertebral body in the multi-detector CT (MDCT) sagittal three-dimensional reconstructed image were measured and compared. At the same time, 60 thoracolumbar adjacent vertebral bodies without fractures were selected from 20 people, and the mean HU value of the trabecular bone region of each vertebra in the MDCT sagittal three-dimensional reconstructed image was measured and compared. RESULTS: There were correlations among the mean HU values of 60 thoracolumbar adjacent vertebral bodies in the 20 people without fractures, and there were no differences in the correlations between middle vertebral body (MV) and upper vertebral body (UV) and between MV and lower vertebral body (LV) compared with the correlation between UV and LV. In the 31 fracture cases, the mean HU values had correlations among TV, UV and LV, there was no difference in the comparison of correlations between TV and UV and between TV and LV, but the correlations between TV and UV and between TV and LV had differences compared with the correlation between UV and LV. CONCLUSIONS: The mean HU value of TV of uncompressed elderly osteoporotic thoracolumbar fractures is increased abnormally compared with that of the adjacent vertebral body, and it is feasible to determine the TV of uncompressed osteoporotic thoracolumbar fractures according to the mean HU value.
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Vértebras Lombares/lesões , Fraturas por Osteoporose/diagnóstico por imagem , Fraturas da Coluna Vertebral/diagnóstico por imagem , Vértebras Torácicas/lesões , Tomografia Computadorizada por Raios X/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Estudos Retrospectivos , Vértebras Torácicas/diagnóstico por imagemRESUMO
A polyethylene glycol (PEG) precipitation F(ab')2 anti-C3 ELISA for the detection of complement-fixing IgG circulating immune complexes (CIC) is described. For this assay, test sera were treated with 3.5% PEG and then measured with F(ab')2 anti-C3 ELISA. The lower detection limit was 4 micrograms/ml of heat aggregated human IgG (HAHG). Intra-assay coefficient of variation (CV) was 4.9-8.3%. High levels of CIC are found in the sera of patients with systemic lupus erythematosus (SLE), hepatitis B and stomach cancer.
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Complexo Antígeno-Anticorpo/análise , Complemento C3/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Fragmentos Fab das Imunoglobulinas/imunologia , Polietilenoglicóis , Precipitação Química , Testes de Fixação de Complemento , Hepatite B/imunologia , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Reprodutibilidade dos Testes , Neoplasias Gástricas/imunologiaRESUMO
A rapid, efficient, routine system has been established for Agrobacterium tumefaciens-mediated production of hundreds of fertile transgenic plants from commercially important rice cultivars, including an indica cultivar, Pusa Basmati 1. Calli induced from embryos of mature rice seeds were cocultivated with A. tumefaciens strain LBA4404 carrying the plasmid pTOK233, then exposed to hygromycin selection followed by an efficient regeneration system. Based on the total number of calli co-cultivated, the transformation frequencies of independent transgenic rice plants including cultivars Pusa Basmati 1, E-yi 105, E-wan 5 and Zhong-shu-wan-geng, were 13.5, 13.0, 9.1, and 9.3%, respectively. T1 seeds were harvested within 7-8 mo of initiation of mature embryo cultures. Data from Southern hybridization analysis proved that foreign genes on T-DNA were stably integrated into the rice genome at low copy/site numbers. Mendelian inheritance of the transgenes was confirmed in T1 progeny.
Assuntos
Agrobacterium tumefaciens/genética , Vetores Genéticos , Oryza/genética , Transformação Genética , Southern Blotting , Plantas Geneticamente ModificadasRESUMO
The stability of epidermal growth factor (EGF) in the gastrointestinal humen of 3-day-old suckling and 45-day-old weaned pigs was examined by incubating iodine labeled recombinant human EGF (hEGF) in the gastrointestinal fluids at 37 degrees C and monitoring the generation of acid soluble radioactivity. Chromatographic analysis and receptor binding study were also undertaken. The results showed that hEGF was quite stable in the gastric fluids in both suckling and weaned pigs with less than 20% degradation after 20 min incubation. The degradation rate in the intestinal fluids varied with the region of the small intestine and the age of the animals. At the proximal and mid regions of the small intestine in suckling pigs the degradation rate of hEGF after 20 min incubation was 5 and 20% respectively, while the degradation rate at the distal region was up to 50%. In the small intestinal lumen in weaned pigs the degradation rate of hEGF was much greater than that in suckling pigs, and the degradation rates at the proximal, mid and distal regions were 33, 51 and 56% respectively. Addition of acid soluble or casein fractions of porcine colostrum markedly reduced the degradation of hEGF in the intestinal fluids. These results indicate that milk-borne EGF is stable in the gastric and proximal intestinal humen in suckling pigs, and may play a role in regulating postnatal development in the suckling young.
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Sistema Digestório/efeitos dos fármacos , Estabilidade de Medicamentos , Fator de Crescimento Epidérmico/química , Animais , Ligação Competitiva , Quimotripsina/química , Relação Dose-Resposta a Droga , Ativação Enzimática , Fator de Crescimento Epidérmico/farmacologia , Humanos , Suínos , Tripsina/químicaRESUMO
Insulinlike growth factor-I (IGF-I) has been found in the milk of various species. To investigate if milk-borne IGF-I has any effect on postnatal gut development in neonatal animals, newborn rat pups were given orally 1 microg recombinant human IGF-I daily for 3 days. For comparison, a separate group of newborn pups was given 150 microg hydrocortisone, the hormone known to stimulate intestinal maturation in neonatal rats. Oral IGF-I treatment had no significant effect on the animal body weight nor on the weight of the stomach, small and large intestines, and pancreas. Oral administration of hydrocortisone significantly reduced body weight gain, but it had no apparent effect on internal organ weights. Both IGF-I and hydrocortisone treatments, however, significantly increased lactase, maltase and sucrase activities and hydrocortisone significantly increased aminopeptidase activity at the proximal small intestine when compared with the control. The finding supports the hypothesis that milk-borne IGF-I may play a role in regulating postnatal gut development in the suckling young.
Assuntos
Fator de Crescimento Insulin-Like I/farmacologia , Intestinos/efeitos dos fármacos , Sacarase/efeitos dos fármacos , alfa-Glucosidases/efeitos dos fármacos , beta-Galactosidase/efeitos dos fármacos , Animais , Animais Recém-Nascidos/fisiologia , Fator de Crescimento Insulin-Like I/administração & dosagem , Ratos , Ratos WistarRESUMO
Stability and distribution of orally administered epidermal growth factor (EGF) were examined in newborn and 5-day-old pigs. Forty-five minutes after oral administration of iodine-125 labeled EGF, 60 and 50% of the radioactivity administered were recovered from the internal organs in newborn and 5-day-old pigs, respectively. In both age groups, over 95% of the recovered radioactivity was found in the gastrointestinal tract, of which 78-86% was found in the luminal contents with the remaining found in the gastrointestinal wall. Within the gastrointestinal tract, 65-71% of radioactivity was found in the stomach, 27-30% in the proximal and mid small intestine and 3-4% was found in the distal part of the small intestine. There were no significant differences in the overall distribution of orally administered radioactivity between two age groups. Based on liquid chromatography and trichloroacetic acid precipitation, a substantial amount of EGF recovered from the luminal contents (63-86%) and the gastrointestinal wall (42-81%) remained "intact". The receptor binding ability of the EGF recovered from the gastric contents was 96-102% comparable to the native EGF tracer. The receptor binding ability remained high (40-58%) in the proximal small intestinal lumen and it decreased to 15% in the distal small intestinal lumen in newborn pigs. In 5-day-old pigs, EGF recovered from the small intestinal contents had 5 to 24% receptor binding ability when compared with native EGF tracer. The receptor binding ability of the EGF recovered from all other organs was below 5% with an exception of the gastric wall, from which recovered EGF retained 9 to 26% receptor binding ability. These results indicate that most of orally ingested EGF remained in the gastrointestinal tract in neonatal pigs 45 min after oral ingestion, and significant amount of the ingested EGF remained biologically active. It suggests that milk-borne EGF can survive in the gastrointestinal tract and may play a role in regulating gut development in neonatal animals.
Assuntos
Animais Recém-Nascidos/metabolismo , Fator de Crescimento Epidérmico/farmacocinética , Administração Oral , Animais , Biotransformação , Cromatografia em Gel , Receptores ErbB/metabolismo , Humanos , Absorção Intestinal , Radioisótopos do Iodo , Proteínas Recombinantes/metabolismo , Suínos , Distribuição TecidualRESUMO
During the immediate postnatal period, the gastrointestinal (GI) tract undergoes profound growth, morphological changes and functional maturation. The oesophagus shows an accelerated cell proliferation in the epithelium and an increased production and accumulation of mucus in the glands. The stomach shows a rapid tissue growth and a marked increase in acid secretion capacity. The intestine shows increased tissue growth and marked epithelial modifications; the latter include the loss of the ability by the epithelial cells of the small intestine to absorb macromolecules, and the loss of the ability by the epithelial cells of the large intestine to synthesize digestive enzymes and to absorb amino acids and glucose. These changes are apparently related to the onset of colostrum ingestion, because starved or water-fed newborns showed little changes in the GI tract. A number of hormones and growth-promoting peptides, such as insulin, cortisol, epidermal growth factor (EGF) and insulin-like growth factor I (IGF-I), have been found at high concentrations in the maternal colostrum. There is evidence that colostrum-bone EGF and IGF-I play a role in postnatal GI development in newborns. The role of other colostrum-borne hormones and growth-promoting peptides remains to be assessed. Further studies are also required to demonstrate if colostrum-borne EGF and IGF-I can be used therapeutically to those newborns with immature or diseased GI tract, such as in cases of premature birth or prenatal growth retardation or cases requiring total parenteral nutrition.
Assuntos
Colostro/metabolismo , Sistema Digestório/crescimento & desenvolvimento , Recém-Nascido/crescimento & desenvolvimento , Fator de Crescimento Epidérmico/fisiologia , Esôfago/crescimento & desenvolvimento , Feminino , Humanos , Fator de Crescimento Insulin-Like I/fisiologia , Fator de Crescimento Insulin-Like II/fisiologia , Gravidez , Estômago/crescimento & desenvolvimentoRESUMO
It has been reported in the literature that the stomach and the intestine in newborns undergo profound growth and functional maturation during the immediate postnatal period and diet ingestion has a significant impact on these changes. The present paper examines oesophageal development in newborn pigs during the first three postnatal days and the effects of diet and oral insulin-like growth factor I (IGF-I) or IGF-II on oesophageal morphology. It was observed that marked changes, including reduction in thickness of the epithelium, accelerated proliferation and migration of basal epithelial cells and increased accumulation of mucus in the glandular cells, occurred during the first postnatal day following onset of natural suckling. Bottle-feeding with various liquid diets (i.e. porcine colostrum, bovine colostrum, bovine milk, and infant milk formula), induced marked morphological changes which were similar to those induced by natural suckling. However, bottle-feeding with water did not result in marked reduction in the thickness of the epithelium nor did it accelerate basal epithelial cell proliferation and migration. Oral IGF-I, but not IGF-II, increased basal epithelial cell proliferation up to 81%. Owing to a large inter-animal variation, the increment did not reach a significant level (P = 0.071). The results suggest that chemical constituents in the diet and physical stimulation of food ingestion, which cause sloughing off of luminal surface tissue, are two major stimuli or epithelial cell proliferation in the new born oesophagus.
Assuntos
Envelhecimento/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Esôfago/anatomia & histologia , Fator de Crescimento Insulin-Like II/farmacologia , Fator de Crescimento Insulin-Like I/farmacologia , Administração Oral , Envelhecimento/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Bromodesoxiuridina/metabolismo , Bovinos , Epitélio/anatomia & histologia , Epitélio/efeitos dos fármacos , Epitélio/crescimento & desenvolvimento , Esôfago/efeitos dos fármacos , Esôfago/crescimento & desenvolvimento , Fator de Crescimento Insulin-Like I/administração & dosagem , Fator de Crescimento Insulin-Like II/administração & dosagem , SuínosRESUMO
A near-infrared spectroscopic technique was developed to detect beef hamburgers adulterated with 5-25% mutton, pork, skim milk powder, or wheat flour with an accuracy up to 92.7%. The accuracy of detection increased with the increase of adulteration level. When an adulterant was detected, the adulteration level was further predicted by calibration equations. The established calibration equations for predicting adulteration levels with mutton, pork, skim milk powder, and wheat flour had standard errors of cross-validation of 3.33, 2.99, 0.92, and 0.57% and coefficients of variance of 0.87, 0.89, 0.99, and 1.00, respectively. The results of this study indicate that near-infrared spectroscopy is potentially useful in detection of beef hamburger adulteration.
Assuntos
Contaminação de Alimentos/análise , Carne/análise , Animais , Bovinos , Farinha , Leite , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria Infravermelho/métodos , Suínos , TriticumRESUMO
The feasibility of using near-infrared spectroscopy to determine chemical composition of commercial honey was examined. The influences of various sample presentation methods and regression models on the performance of calibration equations were also studied. Transmittance spectra with 1 mm optical path length produced the best calibration for all constituents examined. The regression model of modified partial least squares (mPLS) was selected for the calibration of all honey constituents except moisture, for which the optimal calibration was developed with PLS. Validation of the established calibration equations with independent samples showed that the spectroscopic technique could accurately determine the contents of moisture, fructose, glucose, sucrose, and maltose with squared correlation coefficients (R(2)) of 1.0, 0.97, 0.91, 0.86, and 0.93 between the predicted values and the reference values. The prediction accuracy for free acid, lactone, and hydroxymethylfurfural (HMF) contents in honey was poor and unreliable. The study indicates that near-infrared spectroscopy can be used for rapid determination of major components in commercial honey.
Assuntos
Mel/análise , Calibragem , Espectroscopia de Luz Próxima ao InfravermelhoRESUMO
A double-blind clinical trial with praziquantel was carried out. A total of 400 cases was treated with four different dosages, namely, 60, 50, 40 and 30 mg/kg body weight of praziquantel. The drug was given in one day divided into two doses. Identical placebo tablets were used to make up a total of 60 mg/kg. Tolerance was good in all with the exception of one case suffering from asthmatic attack with papule rashes over large area of the body surface. 394 patients were able to be followed up parasitologically six months post-treatment. 79.8%, 71.7%, 78.8% and 70.1% of the patients were negative in the groups with the total dose of 60, 50, 40 and 30 mg/kg respectively. The cure rates as well as the side effects were similar for the four groups. The efficacy was lower than that reported by other authors and the possibility of reinfection was incriminated. In villages with few snails the negative hatching rates in aforementioned four groups were 89.1%, 91.1%, 88.9% and 81.8%, while in villages with abundant snails the rates were 68.2%, 46.5%, 66.7% and 54.8%. The difference between the two areas was statistically significant. Higher efficacy was observed in adults with an average cure rate of 80.0% than in children under 15 years of age, the average cure rate being 57.1%.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Praziquantel/uso terapêutico , Esquistossomose Japônica/tratamento farmacológico , Adolescente , Adulto , Fatores Etários , Criança , Ensaios Clínicos como Assunto , Relação Dose-Resposta a Droga , Método Duplo-Cego , Fezes/parasitologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Praziquantel/administração & dosagem , Praziquantel/efeitos adversos , Fatores Sexuais , Fatores de TempoRESUMO
Transforming growth factor-beta (TGF-beta) plays a role in enterocyte proliferation control, cell differentiation, and immune regulation via binding to specific TGF-beta receptors (TGF-beta R) in the intestinal epithelium. Endogenous TGF-beta production is low in the intestine during the perinatal period, but some exogenous TGF-beta ligands are supplied by amniotic fluid intake in the fetus and by colostrum ingestion in the neonate. It is not clear, however, whether luminal TGF-beta receptors are present and functional at this critical time. We studied intestinal TGF-beta receptors by immunohistochemistry during the last 20% of gestation in pigs and in chronically catheterized fetuses following exposure to colostrum, milk, and amniotic fluid (control). In fetal pigs, the TGF-beta Rs were predominantly localized to the crypt epithelium, but staining intensity increased markedly just before term and shifted to the villous epithelium in newborn pigs, concurrently with marked increases in villous heights and crypt depths (+100-200%, P < 0.05). In contrast to previous observations in term newborn pigs, fetal pigs did not show any milk-induced change in TGF-beta receptor densities or localization, although a moderate increase in villous height was observed, relative to control (+25-50%, P < 0.05). We conclude that intestinal TGF-beta receptor density and localization are immature and unresponsive to TGF-beta containing milk diets in prenatal pigs. Immaturity of TGF-beta-mediated immune regulation may play a role in the increased sensitivity of preterm neonates to diet-induced intestinal inflammatory disorders.
Assuntos
Proliferação de Células , Nutrição Enteral , Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Líquido Amniótico/metabolismo , Animais , Animais Recém-Nascidos , Colostro/metabolismo , Feminino , Idade Gestacional , Humanos , Imunidade nas Mucosas , Fórmulas Infantis/metabolismo , Recém-Nascido , Mucosa Intestinal/embriologia , Mucosa Intestinal/imunologia , Intestino Delgado/embriologia , Intestino Delgado/imunologia , Proteínas do Leite/metabolismo , Gravidez , SuínosRESUMO
The inducible enzyme cyclooxygenase-2 (COX-2) is an important mediator of angiogenesis and tumor growth. Several reports have indicated that vascular endothelial growth factor (VEGF)-positive tumors are associated with an increased amount of COX-2 protein. This study evaluated the significance of COX-2 in 34 patients with endometrial carcinoma and its relationship to angiogenesis. Immunohistochemical expression of COX-2 and VEGF was analyzed on paraffin-embedded tissue sections. Microvessel density (MVD) of endometrial carcinoma was also determined with anti-CD(34) as the label. COX-2 messenger RNA (mRNA) was analyzed by reverse transcription-polymerase chain reaction. The expression rate of COX-2 in 34 cases was 64.7% but not in control endometrium. COX-2 mRNA was higher in tumor specimens than in normal tissues. The level of COX-2 expression was higher in grade 2 tumors than in grade 3 tumors (P < 0.05). MVD was higher in COX-2-positive and VEGF-positive cases than in COX-2-negative and VEGF-negative cases (P < 0.05). The expression of COX-2 was positively correlated with the expression of VEGF and MVD (P < 0.05 and P < 0.01, respectively). The present findings suggest that overexpression of COX-2 may induce the expression of VEGF, increase angiogenesis, and enhance tumor growth.
Assuntos
Ciclo-Oxigenase 2/metabolismo , Neoplasias do Endométrio/metabolismo , Neovascularização Patológica/metabolismo , Adulto , Idoso , Neoplasias do Endométrio/irrigação sanguínea , Neoplasias do Endométrio/patologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Masculino , Microcirculação , Pessoa de Meia-Idade , Miométrio/metabolismo , Miométrio/patologia , Invasividade Neoplásica/patologia , Neovascularização Patológica/patologia , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
1. Specific [3H]estradiol binding activity with characteristics of estrogen receptors was found in the cytosols and nuclear extracts of the adrenal cortex proper and special zone of the brushtail possum (Trichosurus vulpecula). 2. The specific estradiol receptor had a sedimentation coefficient on sucrose gradients of approximately 9S and a molecular weight on gel filtration of more than 200,000. The adrenal cortex cytosol binds [3H]estradiol with high affinity (Ka 5.5 X 10(9) M-1), and limited capacity (Bmax 62.7 fmol/mg cytosol prot). In competition experiments with different steroids the receptor showed a high affinity for four estrogens and a very low affinity to androgens, progesterone and cortisol. 3. There was no difference in the affinity and maximum binding capacity of the cytosols from cortex proper in male and female animals, but the binding capacity of the special zone of females was half that of cortex proper. Estradiol receptors were found in the kidney, liver, lung, testis and muscle but only in the adrenal and prostate was the binding capacity relatively high compared with the uterus. 4. The specific binding capacity of [3H]estradiol to cytosols of adrenal cortex at different stages of the estrus cycle and pregnancy was unrelated to that of the uterus. In the adrenal the receptor concentration was lowest at estrus, when uterine concentration was high, while in late pregnancy the binding of adrenal cortex and uterus cytosols was almost the same. 5. The possible physiological significance of the presence of a specific estrogen receptor in male and female possums is discussed.
Assuntos
Córtex Suprarrenal/metabolismo , Receptores de Estradiol/metabolismo , Animais , Ligação Competitiva , Cromatografia em Gel , Citosol/metabolismo , Estradiol/metabolismo , Feminino , Cinética , Masculino , Gambás , Especificidade de Órgãos , Receptores de Estradiol/isolamento & purificação , Fatores SexuaisRESUMO
The development of the gastric acid secretory response to pentagastrin was studied using 56 Large White x Landrace pigs, 0-36 days of age, 1.1-13.3 kg body-weight, obtained from 12 litters. Gastric acid secretory capacity was measured using a gastric perfusion technique and intravenous infusion of pentagastrin at dose rates of 2, 4 and 8 micrograms/h per kg. Significant positive linear correlations were found between stomach weight and age, and between stomach weight and body-weight during the 36 day period. The stomach weight to body-weight ratio increased for the first 3 days of age and then decreased during the following 33 days. Basal acid secretion was detected in all unsuckled pigs (n = 9), 2- to 8-h old. Maximal acid outputs in response to pentagastrin in these pigs were 0.16 +/- 0.02 mmol/kg body-weight and 0.034 +/- 0.001 mmol/g stomach weight. For the 56 pigs, significant linear correlations were found between maximal acid output and age, maximal acid output and body-weight, and maximal acid output and stomach weight. There was a significant linear increase in maximal acid output per unit stomach weight during the first 7 days of age, but during the subsequent 29 days the pattern of increase in gastric secretory capacity was slower and curvilinear. In the oldest nine pigs, 24-36 days of age, maximal acid outputs were 0.974 +/- 0.058 mmol/kg body-weight and 0.234 +/- 0.016 mmol/g stomach weight which represents a six to seven-fold increase compared with those determined in pigs at birth. Comparison of gastric acid secretory capacity determined under anaesthesia with that in conscious pigs showed that anaesthesia appeared to suppress basal output but had no effect on pentagastrin stimulated output. Comparison of response to histalog (betazole HCl) and pentagastrin indicated that newborn pigs were more sensitive to histalog but in pigs 9-38 days of age, there were no significant differences in responsiveness to the two secretagogues. These results show that gastric sensitivity to pentagastrin increases rapidly in the first week of life, that the stomach of the newborn pig is more sensitive to histalog than pentagastrin and that studies of the effect of pentagastrin on acid secretion, done under anaesthesia, are comparable to those in the conscious pig.