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1.
Endocr Connect ; 7(12): 1442-1447, 2018 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-30475222

RESUMEN

Aims Physical activity has been proposed to be an effective non-pharmacological method of reducing systemic inflammation and therefore may prove particularly efficacious for women with polycystic ovary syndrome (PCOS) who have been shown to have high levels of inflammation and an increased risk of type 2 diabetes (T2DM) and cardiovascular disease (CVD). Therefore, the aim of the present study was to assess whether modest changes in daily step count could significantly reduce levels of inflammatory markers in women with PCOS. Subjects and Methods Sixty-five women with PCOS were assessed at baseline and again at 6 months. All had been provided with an accelerometer and encouraged to increase activity levels. Multivariate linear regression analyses (adjusted for age, ethnicity, baseline step count, change in BMI and change in accelerometer wear-time) were used to assess changes in daily step count against clinical and research biomarkers of inflammation, CVD and T2DM. Results Mean step count/day at baseline was 6337 (±270). An increase in step count (by 1000 steps) was associated with a 13% reduction in IL6 (ß: -0.81 ng/L; 95% CI, -1.37, -0.25, P = 0.005) and a 13% reduction in CRP (ß: -0.68 mg/L; 95% CI, -1.30, -0.06, P = 0.033). Additionally, there was a modest decrease in BMI (ß: 0.20 kg/m2; 95% CI, -0.38, -0.01, P = 0.038). Clinical markers of T2DM and CVD were not affected by increased step count. Conclusions Modest increases in step count/day can reduce levels of inflammatory markers in women with PCOS, which may reduce the future risk of T2DM and CVD.

2.
Food Res Int ; 105: 548-555, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29433246

RESUMEN

Bubbles, found in a huge variety of food products, are known to afford desirable quality attributes, especially those related to texture, mouthfeel and taste. However, the presence of bubbles and their effects on wheat flour noodles is an aspect that has been, until now, largely overlooked, despite the positive and negative connotations of bubbly inclusions on Asian noodle quality. X-rays from a synchrotron source (Biomedical Imaging and Therapy facility at the Canadian Light Source) were used to rapidly and non-destructively acquire tomographic images of noodle dough. Appropriate image analysis protocols were used to determine the bubble size distribution, the orientation of bubbles, and their position within the dough sheet. The effect of processing (one or multiple lamination steps) on bubble properties in the dough that was subsequently sheeted (gradual elongation and reduction in thickness) was investigated. Bubble size distributions, well captured by lognormal distribution function, showed that the lamination process induced bubble entrapment and reduction in bubble size. Bubbles were found to be flat, elongated and oriented in the sheeting direction, this effect being less for doughs laminated ten times (90° rotations between lamination steps). Interestingly, a gradient in concentration of bubbles within the dough sheet was found from the noodle core to the sheet edges. Aging effects were also apparent. This first non-destructive study of bubbles in wheat-flour noodle dough provides a more complete knowledge of the dough sheet's internal structure, and how it originates via processing, and this has repercussions on the overall quality of Asian noodles.


Asunto(s)
Aire/análisis , Culinaria/métodos , Harina/análisis , Manipulación de Alimentos/métodos , Triticum , Microtomografía por Rayos X , Difusión , Sincrotrones
3.
Phys Med ; 32(12): 1753-1758, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27453203

RESUMEN

The BioMedical Imaging and Therapy (BMIT) facility [1,2] located at the Canadian Light Source, provides synchrotron-specific imaging and radiation therapy capabilities. There are two separate beamlines used for experiments: the bending magnet (05B1-1) and the insertion device (05ID-2) beamline. The bending magnet beamline provides access to monochromatic beam spanning a spectral range of 15-40keV, and the beam is 240mm wide in the POE-2 experimental hutch. Users can also perform experiments with polychromatic (pink) beam. The insertion device beamline was officially opened for general user program in 2015. The source for the ID beamline is a multi-pole, superconducting 4.3T wiggler. The high field gives a critical energy over 20keV. The optics hutches prepare a beam that is 220mm wide in the last experimental hutch SOE-1. The monochromatic spectral range spans 25-150+keV. Several different X-ray detectors are available for both beamlines, with resolutions ranging from 2µm to 200µm. BMIT provides a number of imaging techniques including standard absorption X-ray imaging, K-edge subtraction imaging (KES), in-line phase contrast imaging (also known as propagation based imaging, PBI) and Diffraction Enhanced Imaging/Analyzer Based Imaging (DEI/ABI), all in either projection or CT mode. PBI and DEI/ABI are particularly important tools for BMIT users since these techniques enable visualization of soft tissue and allow for low dose imaging.


Asunto(s)
Sincrotrones , Tomografía Computarizada por Rayos X/instrumentación , Animales , Canadá , Respiración , Sistema Respiratorio/diagnóstico por imagen , Porcinos
4.
Cell Transplant ; 22(6): 1041-51, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23007077

RESUMEN

Islet autotransplant patients represent excellent subjects to assess the posttransplant impact of islet precursors, as chronic pancreatitis (CP) causes an elevation of ductal cells, pancreatic precursors cells, and hormone-positive acinar cells. The relationship between these cell types and autograft outcomes should be more apparent than would be the case in the context of an allograft program with confounding immunological variables. To improve diabetic control following total pancreatectomy for CP, nonpurified islets were autotransplanted into the liver. Pancreas specimens were recovered from 23 patients and stained for antigens including: insulin, glucagon, cytokeratin 19, cytokeratin 7, and PDX-1. In line with previous reports, the prevalence of ductal cells, non-islet endocrine cells and non-islet PDX-1-expressing cells was significantly higher in CP glands compared with normal pancreata. When correlating follow-up data (i.e., fasting and stimulated C-peptide/glucose levels and HbA1c%) with pancreas immunoreactivity, high levels of ductal cells, non-islet PDX-1-positive cells, and non-islet glucagon-positive cells were associated with superior outcomes, detectable up to 2 years posttransplant. To conclude, the acinar parenchyma and ductal epithelium of the CP pancreas show an upregulation of both endocrine and pre-endocrine cell types, which appear to have a positive effect on islet graft outcomes in autotransplantation setting.


Asunto(s)
Trasplante de Islotes Pancreáticos , Islotes Pancreáticos/citología , Células Madre/citología , Biomarcadores/metabolismo , Células Epiteliales/metabolismo , Células Epiteliales/patología , Glucagón/metabolismo , Proteínas de Homeodominio/metabolismo , Humanos , Insulina/metabolismo , Queratinas/metabolismo , Conductos Pancreáticos/metabolismo , Conductos Pancreáticos/patología , Pancreatitis Crónica/metabolismo , Pancreatitis Crónica/patología , Transactivadores/metabolismo , Trasplante Autólogo
5.
J Phys Condens Matter ; 21(39): 395801, 2009 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-21832397

RESUMEN

(As(0.4)S(0.6))(100-x)Ag(x) glasses (x = 0, 4, 8, 12 at.%) have been studied with high-energy x-ray diffraction, neutron diffraction and extended x-ray absorption spectroscopy at As and Ag K-edges. The experimental data were modelled simultaneously with the reverse Monte Carlo simulation method. Analysis of the partial pair correlation functions and coordination numbers extracted from the model atomic configurations revealed that silver preferentially bonds to sulfur in the As(2)S(3)-Ag ternary glasses, which results in the formation of homoatomic As-As bonds. Upon the addition of Ag, a small proportion of Ag-As bonds (N(AgAs)≈0.3) are formed in all three ternary compositions, while the direct Ag-Ag bonds (N(AgAg)≈ 0.4) appear only in the glass with the highest Ag content (12 at.%). Similar to the g- As(2)S(3) binary, the mean coordination number of arsenic is close to three, and that of sulfur is close to two, in the As(2)S(3)-Ag ternary glasses. The first sharp diffraction peak on the total structure factors of As(2)S(3) binary and (As(0.4)S(0.6))(100-x)Ag(x) ternary glasses is related to the As-As and As-S correlations.

6.
Bull Environ Contam Toxicol ; 81(3): 225-9, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18421403

RESUMEN

Organochlorine (OC) pesticide concentrations in blood plasma samples from 88 juvenile white sturgeon collected from the lower Columbia River were measured and compared to plasma sex steroid and OC tissue levels previously measured in corresponding fish. Significant squared correlation coefficients between summation operator DDT concentrations in sturgeon plasma and gonads and livers were 0.37 and 0.32, respectively. Significant negative correlations between plasma testosterone concentration and plasma Sigma DDT concentration in male fish (r(2)=0.26), plasma 17beta estradiol concentration and plasma Sigma DDT concentration in female fish (r(2)=0.38) and condition factor and plasma Sigma DDT concentration in all fish were found (r(2)=0.17). These results suggest that blood plasma may be a suitable nondestructive method for monitoring adult sturgeon population for persistent OC contaminants.


Asunto(s)
Monitoreo del Ambiente/métodos , Peces/sangre , Hidrocarburos Clorados/sangre , Plaguicidas/sangre , Ríos/química , Contaminantes Químicos del Agua/sangre , Animales , Femenino , Hormonas Esteroides Gonadales/sangre , Masculino , Oregon
7.
Arch Environ Contam Toxicol ; 50(3): 443-51, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16446999

RESUMEN

This study determined the partitioning of total mercury in liver, gonad, and cheek muscle of white sturgeon (Acipenser transmonatus) in the lower Columbia River. The relationship between tissue mercury concentrations and various physiologic parameters was assessed. White sturgeon were captured in commercial fisheries in the estuary and Bonneville, The Dalles, and John Day Reservoirs. Condition factor (CF), relative weight (Wr), and gonadosomatic index (GSI) were determined for each fish (n = 57). Gonadal tissue was examined histologically to determine sex and stage of maturity. Liver (n = 49), gonad (n = 49), and cheek muscle (n = 57) were analyzed for total mercury using cold-vapor atomic fluorescence spectrophotometry. Tissue protein concentrations were measured by ultraviolet-visible spectroscopy. Plasma was analyzed for testosterone (T), 11-ketotestosterone (KT), and 17ss-estradiol (E2) using radioimmunoassay. Mean tissue mercury concentrations were higher in muscle compared with liver and gonad at all sampling locations, except Bonneville Reservoir where mean liver mercury content was the highest tissue concentration observed in the study. Significant negative correlations between plasma androgens (T and KT) and muscle mercury content and plasma E2 and liver mercury content were found. A significant positive linear relationship between white sturgeon age and liver mercury concentrations was evident. Significant negative correlations between CF and relative weight and gonad and liver mercury content were found. In addition, immature male sturgeon with increased gonad mercury content had decreased GSIs. These results suggest that mercury, in the form of methylmercury, may have an effect on the reproductive potential of white sturgeon.


Asunto(s)
Peces/metabolismo , Mercurio/análisis , Contaminantes Químicos del Agua/análisis , Factores de Edad , Animales , Estradiol/sangre , Femenino , Peces/anatomía & histología , Gónadas/anatomía & histología , Gónadas/química , Hígado/química , Masculino , Mercurio/metabolismo , Músculos/química , Reproducción , Ríos , Testosterona/análogos & derivados , Testosterona/sangre , Contaminantes Químicos del Agua/metabolismo
8.
Prostate Cancer Prostatic Dis ; 6(2): 148-53, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12806374

RESUMEN

We assessed the relative levels of secreted matrix metalloproteinases (MMPs) and plasminogen activators (PAs) in PC-3 cells, prostate fibroblasts and osteoblasts in the presence and absence of VEGF, TGF beta1 and bFGF. Fibroblasts and osteoblasts secreted more MMPs -1 and -2 than did PC-3 cells, while PC-3 s contributed the majority of PAs. MMP-1 expression was downregulated by transforming growth factor beta-1 (TGF beta1) treatment in prostate fibroblasts and upregulated by basic fibroblast growth factor (bFGF) in both stromal lines. In PC-3 cells, TGF beta1 and bFGF increased urokinase plasminogen activator secretion. TGF beta1 decreased tissue plasminogen activator secretion in all cell lines. Prostate cancer cells associated with fibroblasts or osteoblasts have a variety of MMPs and PAs to facilitate matrix degradation.


Asunto(s)
Factor 2 de Crecimiento de Fibroblastos/farmacología , Metaloproteinasas de la Matriz/metabolismo , Osteoblastos/fisiología , Activadores Plasminogénicos/metabolismo , Próstata/citología , Neoplasias de la Próstata/patología , Factor de Crecimiento Transformador beta/farmacología , Factor A de Crecimiento Endotelial Vascular/farmacología , Animales , Matriz Extracelular/metabolismo , Fibroblastos/fisiología , Masculino , Células Tumorales Cultivadas , Regulación hacia Arriba
9.
Cell Stress Chaperones ; 6(3): 247-55, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11599566

RESUMEN

The Hsp70-interacting protein Hip binds to the adenosine triphosphatase domain of Hsp70, stabilizing it in the adenosine 5'-diphosphate-ligated conformation and promoting binding of target polypeptides. In mammalian cells, Hip is a component of the cytoplasmic chaperone heterocomplex that regulates signal transduction via interaction with hormone receptors and protein kinases. Analysis of the complete genome sequence of the model flowering plant Arabidopsis thaliana revealed 2 genes encoding Hip orthologs. The deduced sequence of AtHip-1 consists of 441 amino acid residues and is 42% identical to human Hip. AtHip-1 contains the same functional domains characterized in mammalian Hip, including an N-terminal dimerization domain, an acidic domain, 3 tetratricopeptide repeats flanked by a highly charged region, a series of degenerate GGMP repeats, and a C-terminal region similar to the Sti1/Hop/p60 protein. The deduced amino acid sequence of AtHip-2 consists of 380 amino acid residues. AtHip-2 consists of a truncated Hip-like domain that is 46% identical to human Hip, followed by a C-terminal domain related to thioredoxin. AtHip-2 is 63% identical to another Hip-thioredoxin protein recently identified in Vitis labrusca (grape). The truncated Hip domain in AtHip-2 includes the amino terminus, the acidic domain, and tetratricopeptide repeats with flanking charged region. Analyses of expressed sequence tag databases indicate that both AtHip-1 and AtHip-2 are expressed in A thaliana and that orthologs of Hip are also expressed widely in other plants. The similarity between AtHip-1 and its mammalian orthologs is consistent with a similar role in plant cells. The sequence of AtHip-2 suggests the possibility of additional unique chaperone functions.


Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Chaperonas Moleculares/genética , Secuencia de Aminoácidos , Animales , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Proteínas HSP70 de Choque Térmico/metabolismo , Humanos , Chaperonas Moleculares/química , Chaperonas Moleculares/metabolismo , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Secuencias Repetitivas de Ácidos Nucleicos/genética , Alineación de Secuencia , Vitis/genética
10.
Plant Physiol ; 107(2): 435-41, 1995 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-7724672

RESUMEN

Allantoinase (allantoin amidohydrolase, EC 3.5.2.5) catalyzes the conversion of allantoin to allantoic acid in the final step of ureide biogenesis. We have purified allantoinase more than 4000-fold by immunoaffinity chromatography from root nodules and cotyledons of soybean (Glycine max [L] Merr.). We characterized and compared properties of the enzyme from the two sources. Seed and nodule allantoinases had 80% identity in the first 24 amino acid residues of the N terminus. Two-dimensional gel electrophoresis of the purified enzymes showed that multiple forms were present in each. Allantoinases from nodules and cotyledons had very low affinity for allantoin with a Km for allantoin of 17.3 mM in cotyledons and 24.4 mM in nodules. Both had activity in a broad range of pH values from 6.5 to 7.5. In addition, purified allantoinase from both sources was very heat stable. Enzyme activity was stable after 1 h at 70 degrees C, decreased gradually with heating to 85 degrees C, and was lost at 90 to 95 degrees C. Although these studies have revealed some differences between allantoinases in seeds and nodules, the differences were not reflected in key enzyme properties. The immunoaffinity approach enabled purification of allantoinase from soybean root nodules and simplified its purification from cotyledons, thereby allowing characterization and comparison of the enzyme from the two sources.


Asunto(s)
Amidohidrolasas/aislamiento & purificación , Glycine max/enzimología , Amidohidrolasas/química , Amidohidrolasas/metabolismo , Secuencia de Aminoácidos , Anticuerpos , Cromatografía de Afinidad , Cotiledón/enzimología , Electroforesis en Gel de Poliacrilamida , Cinética , Datos de Secuencia Molecular , Raíces de Plantas/enzimología , Homología de Secuencia de Aminoácido , Termodinámica
12.
Plant Physiol ; 103(4): 1235-41, 1993 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8290630

RESUMEN

Allantoinase catalyzes the hydrolysis of allantoin to allantoic acid, a reaction important in both biogenesis and degradation of ureides. Ureide production in cotyledons of germinating soybean (Glycine max L.) seeds has not been studied extensively but may be important in mobilizing nitrogen reserves. Allantoinase was purified approximately 2500-fold from a crude extract of soybean seeds by differential centrifugation, heat treatment, ammonium sulfate fractionation, ethanol fractionation, and fast protein liquid chromatography (Pharmacia) with Mono-Q and Superose columns. The purified enzyme had a subunit size of 30 kD. Polyclonal antibodies produced against the purified protein titrated allantoinase activity in a crude extract of seed proteins. Antibodies recognized the 30-kD band in western blot analysis of crude seed extracts, indicating that they were specific for allantoinase.


Asunto(s)
Amidohidrolasas/aislamiento & purificación , Glycine max/enzimología , Amidohidrolasas/genética , Amidohidrolasas/inmunología , Secuencia de Aminoácidos , Animales , Formación de Anticuerpos , Especificidad de Anticuerpos , Datos de Secuencia Molecular , Peso Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Proteínas de Plantas/aislamiento & purificación , Conformación Proteica , Semillas/enzimología , Glycine max/genética , Glycine max/inmunología
13.
Plant Cell ; 5(8): 941-52, 1993 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8400872

RESUMEN

Higher plants possess several classes of peroxisomes that are present at distinct developmental stages and serve different metabolic roles. To investigate the cellular processes that regulate developmental transitions of peroxisomal function, we analyzed the targeting of glyoxysomal proteins to leaf-type and root peroxisomes. We transferred genes encoding the glyoxysome-specific enzymes isocitrate lyase (IL) and malate synthase into Arabidopsis plants and showed, in cell fractionation and immunogold localization experiments, that the glyoxysomal proteins were imported into leaf-type and root peroxisomes. We next defined the sequences that target IL to peroxisomes and asked whether the same targeting determinant is recognized by different classes of the organelle. By localizing deletion and fusion derivatives of IL, we showed that the polypeptide's carboxyl terminus is both necessary for its transport to peroxisomes and sufficient to redirect a passenger protein from the cytosol to both glyoxysomes and leaf-type peroxisomes. Thus, glyoxysomal proteins are transported into several classes of peroxisomes using a common targeting determinant, suggesting that protein import does not play a regulatory role in determining a peroxisome's function. Rather, the specific metabolic role of a peroxisome appears to be determined primarily by processes that regulate the synthesis and/or stability of its constituent proteins. These processes are specified by the differentiated state of the cells in which the organelles are found.


Asunto(s)
Arabidopsis/metabolismo , Secuencia de Aminoácidos , Arabidopsis/genética , Arabidopsis/ultraestructura , Secuencia de Bases , ADN Complementario/genética , Genes de Plantas , Isocitratoliasa/genética , Isocitratoliasa/metabolismo , Malato Sintasa/genética , Malato Sintasa/metabolismo , Microcuerpos/metabolismo , Microcuerpos/ultraestructura , Microscopía Inmunoelectrónica , Datos de Secuencia Molecular , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente
14.
BMJ ; 304(6821): 220-5, 1992 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-1739796

RESUMEN

OBJECTIVE: To study cause specific mortality of radiation workers with particular reference to associations between fatal neoplasms and level of exposure to radiation. DESIGN: Cohort study. SETTING: United Kingdom. SUBJECTS: 95,217 radiation workers at major sites of the nuclear industry. MAIN OUTCOME MEASURE: Cause of death. RESULTS: Most standardised mortality ratios were below 100: 83 unlagged, 85 with a 10 year lag for all causes; 84 unlagged, 86 lagged for all cancers; and 80 for all known other causes, indicating a "healthy worker effect." The deficit of lung cancer (75 unlagged, 76 lagged) was significant at the 0.1% level. Standardised mortality ratios were significantly raised (214 unlagged, 303 lagged) for thyroid cancer, but there was no evidence for any trend with external recorded radiation dose. Dose of external radiation and mortality from all cancers were weakly correlated (p = 0.10), and multiple myeloma was more strongly correlated (p = 0.06); for leukaemia, excluding chronic lymphatic, the trend was significant (p = 0.03; all tests one tailed). The central estimates of lifetime risk derived from these data were 10.0% per Sv (90% confidence interval less than 0 to 24%) for all cancers and 0.76% per Sv (0.07 to 2.4%) for leukaemia (excluding chronic lymphatic leukaemia). These are, respectively, 2.5 times and 1.9 times the risk estimates recommended by the International Commission on Radiological Protection, but 90% confidence intervals are large and the commission's risk factors fall well within the range. The positive trend with dose for all cancers, from which the risk estimate was derived, was not significant. The positive association between leukaemia (except chronic lymphatic leukaemia) was significant and robust in subsidiary analyses. This study showed no association between radiation exposure and prostatic cancer. CONCLUSION: There is evidence for an association between radiation exposure and mortality from cancer, in particular leukaemia (excluding chronic lymphatic leukaemia) and multiple myeloma, although mortality from these diseases in the study population overall was below that in the general population. The central estimates of risk from this study lie above the most recent estimates of the International Commission on Radiological Protection for leukaemia (excluding chronic lymphatic leukaemia) and for all malignancies. However, the commission's risk estimates are well within the 90% confidence intervals from this study. Analysis of combined cohorts of radiation workers in the United States indicated lower risk estimates than the commission recommends, and when the American data are combined with our analysis the overall risks are close to those estimated by the commission. This first analysis of the National Registry for Radiation Workers does not provide sufficient evidence to justify a revision in risk estimates for radiological protection purposes.


Asunto(s)
Neoplasias Inducidas por Radiación/etiología , Energía Nuclear , Enfermedades Profesionales/etiología , Exposición Profesional/estadística & datos numéricos , Sistema de Registros , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mortalidad , Neoplasias/mortalidad , Enfermedades Profesionales/mortalidad , Dosis de Radiación , Factores de Riesgo , Reino Unido/epidemiología
15.
Planta ; 172(2): 162-75, 1987 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24225867

RESUMEN

Cowpea (Vigna unguiculata (L.) Walp.) nodules have been investigated by means of cytochemical and immunocytochemical procedures at the ultrastructural level in order to assess the role of the uninfected cells in ureide biogenesis. Uricase activity in the nodules was shown by cytochemical methods to be localized exclusively in the numberous large peroxisomes confined to the uninfected cells; the small peroxisomes in the infected cells did not stain for uricase. Uricase was also localized in the peroxisomes of uninfected cells by immunogold techniques employing polyclonal antibodies against nodule-specific uricase of soybean. There was no labeling above background of any structures in the infected cells. The results indicate that the uninfected cells are essential for ureide biogenesis in cowpea. Although tubular endoplasmic reticulum, the presumptive site of allantoinase, increases greatly in the uninfected cells during nodule development, it virtually disappears as the nodules mature. The inconsistency between the disappearance of the tubular endoplasmic reticulum from older nodules and the high allantoinase activity reported for older plants remains to be explained.

17.
East Econ J ; 11(2): 145-55, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-12314225

RESUMEN

PIP: The impact of the brain drain on the educational systems of the countries of origin is examined, with particular reference to governmental decisions concerning education subsidies and the market for educational services. Two hypothetical cases are considered, one in which governments increase expenditures for education in the presence of a widespread brain drain, the other in which they decrease such expenditures.^ieng


Asunto(s)
Países en Desarrollo , Educación , Emigración e Inmigración , Administración Financiera , Financiación Gubernamental , Gobierno , Gastos en Salud , Política Pública , Demografía , Economía , Política , Población , Dinámica Poblacional
18.
J Public Econ ; 26(2): 249-62, 1985 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-12267542

RESUMEN

This study is concerned with the implications of the brain drain. "The brain drain alters both the endowments of educated labor and the cost of increasing the endowment of such labor in both countries of immigration and emigration." It thus affects government subsidies for education both directly and indirectly. "This has implications for the burden of education expenditures and net supplies of educated labor in a world with a brain drain. The [author] shows the need for inclusion of a mechanism for transfers between the involved governments if a compensation scheme is to yield Pareto efficient migration."


Asunto(s)
Educación , Escolaridad , Emigración e Inmigración , Empleo , Financiación Gubernamental , Fuerza Laboral en Salud , Modelos Teóricos , Características de la Población , Planificación Social , Demografía , Economía , Administración Financiera , Población , Dinámica Poblacional , Clase Social , Factores Socioeconómicos
20.
Science ; 214(4523): 936-8, 1981 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-6795717

RESUMEN

When two small doses of ethanol were administered to pregnant mice during the gastrulation stage of embryogenesis, the embryos developed craniofacial malformations closely resembling those seen in the human fetal alcohol syndrome. Striking histological changes appeared in the developing brain (neuroectoderm) within 24 hours of exposure. Decreased development of the neural plate and its derivatives apparently accounts for the craniofacial malformations. The critical exposure period is equivalent to the third week in human pregnancy.


Asunto(s)
Embrión de Mamíferos/efectos de los fármacos , Etanol/farmacología , Trastornos del Espectro Alcohólico Fetal/fisiopatología , Animales , Niño , Modelos Animales de Enfermedad , Embrión de Mamíferos/ultraestructura , Anomalías del Ojo , Femenino , Humanos , Ratones , Ratones Endogámicos C57BL , Microscopía Electrónica de Rastreo , Embarazo
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