Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
1.
Braz J Biol ; 84: e259454, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35730810

RESUMO

Ananas ananassoides (Baker) L.B.Sm. is a wild pineapple, commonly found in the savannas. This study aimed to describe the morpho-anatomy and histochemistry of its seed. The observations were made in the longitudinal and transverse sections, using an optical microscope. The cell arrangement in the seed coat, ripples in the integument, the ratio of embryo size and endosperm amount, and the number of strata in the aleurone layer are anatomical characteristics that may contribute to distinguishing this species. The starch in the endosperm, lipids and proteins in the embryo, constitute the seed's main nutritional reserves. The homogeneous embryo and phenolic compounds present in the seed coat and in the aleurone layer possibly contribute to the dormancy in this species. This study presents information relevant to the taxonomy and physiology of A. ananassoides, which represents contributions to the global knowledge of this species with a high potential as ornamental.


Assuntos
Ananas , Endosperma/metabolismo , Pradaria , Sementes/química
2.
Med Eng Phys ; 83: 82-92, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32807352

RESUMO

The present work describes the motion of aqueous humor through the anterior chamber and the trabecular drainage system, considering several distributions of the collector channels. The 3D computational model, implemented into the open-source software, was reconstructed from an optical coherence tomography. The model has been employed to simulate the aqueous humor dynamics considering buoyancy effects. The presence of the anterior chamber, the trabecular meshwork, and the Schlemm's canal were taken into consideration with 14 different distributions of collector channels. The influence of collector channels position on the intraocular pressure and shear stress has been analyzed, for a healthy and a glaucomatous condition. Aqueous humor velocity, pressure, temperature, wall shear stress, skin friction coefficient and Nusselt number, are presented for the different cases. The results indicate that the position of the collector channels has a strong influence on the wall shear stress on the Schlemm's canal and collector channels.


Assuntos
Humor Aquoso , Glaucoma , Câmara Anterior , Humanos , Pressão Intraocular , Malha Trabecular
3.
Rev. esp. cir. ortop. traumatol. (Ed. impr.) ; 64(4): 244-250, jul.-ago. 2020. ilus, tab
Artigo em Espanhol | IBECS | ID: ibc-197329

RESUMO

ANTECEDENTES Y OBJETIVO: El cartílago articular (CA) siempre está afectado en cualquier articulación con artrosis (A). La ecografía puede ser una herramienta útil en la monitorización de los cambios en el CA. El propósito del presente estudio es medir ecográficamente el grosor del CA en el fémur distal en jóvenes estudiantes y determinar su relación con el índice de masa corporal (IMC), masa muscular, grasa corporal y la práctica deportiva. MATERIALES Y MÉTODOS: Se realizó un estudio transversal observacional con voluntarios sanos, entre 15 y 25 años. Se recogieron datos antropométricos y se midió el grosor del cartílago femoral de la rodilla en cinco puntos. Además, se midió en un subgrupo el porcentaje de músculo y de grasa corporal. RESULTADOS: En el estudio se incluyeron 100 sujetos. La edad promedio fue de 20 años (± 2,5). El IMC promedio fue 23 kg/m2 (± 3,1). El CA tuvo un mayor grosor en los hombres y en los deportistas vs. las mujeres y los sedentarios, con diferencia estadísticamente significativa. Al comparar el IMC con el grosor del CA no se encontró ninguna relación significativa; sin embargo, sólo dos participantes tenían IMC > 30. CONCLUSIONES: El grosor del cartílago tiene una relación directamente proporcional con el porcentaje de músculo, e inversamente proporcional con el porcentaje de grasa. El IMC no es un buen parámetro al evaluar el comportamiento dinámico del cartílago en jóvenes no obesos


BACKGROUND AND OBJECTIVE: Articular cartilage (AC) is always affected in any joint with osteoarthritis. Ultrasound can be a useful tool in monitoring changes in the AC. The purpose of the present study is to ultrasound measure the thickness of the AC in the distal femur in young students and determine its relationship with body mass index (BMI), muscle mass, body fat and sports practice. MATERIALS AND METHODS: An observational cross-sectional study was conducted with healthy volunteers, between 15 and 25 years old. Anthropometric data were collected and the thickness of the femoral cartilage of the knee was measured at 5 points. In addition, the percentage of muscle and body fat was measured in a subgroup. RESULTS: 100 subjects were included in the study. The average age was 20 years (± 2.5). The average BMI was 23 kg/m2 (± 3.1). AC was thicker in men and sportsmen, versus women and sedentary people, with a statistically significant difference. When comparing BMI with AC thickness no significant relationship was found; however, only 2 participants had BMI > 30. CONCLUSIONS: Cartilage thickness has a direct relationship with the percentage of muscle, and inversely with the percentage of fat. BMI is not a good parameter when evaluating the dynamic behaviour of cartilage in non-obese youths


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Articulação do Joelho/anatomia & histologia , Cartilagem Articular/diagnóstico por imagem , Composição Corporal/fisiologia , Esportes/estatística & dados numéricos , Voluntários Saudáveis/estatística & dados numéricos , Variação Biológica da População , Índice de Massa Corporal , Ultrassonografia/métodos , Estudos Transversais , Impedância Elétrica
4.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-32499158

RESUMO

BACKGROUND AND OBJECTIVE: Articular cartilage (AC) is always affected in any joint with osteoarthritis. Ultrasound can be a useful tool in monitoring changes in the AC. The purpose of the present study is to ultrasound measure the thickness of the AC in the distal femur in young students and determine its relationship with body mass index (BMI), muscle mass, body fat and sports practice. MATERIALS AND METHODS: An observational cross-sectional study was conducted with healthy volunteers, between 15 and 25 years old. Anthropometric data were collected and the thickness of the femoral cartilage of the knee was measured at 5 points. In addition, the percentage of muscle and body fat was measured in a subgroup. RESULTS: 100 subjects were included in the study. The average age was 20 years (± 2.5). The average BMI was 23 kg/m2 (± 3.1). AC was thicker in men and sportsmen, versus women and sedentary people, with a statistically significant difference. When comparing BMI with AC thickness no significant relationship was found; however, only 2 participants had BMI > 30. CONCLUSIONS: Cartilage thickness has a direct relationship with the percentage of muscle, and inversely with the percentage of fat. BMI is not a good parameter when evaluating the dynamic behaviour of cartilage in non-obese youths.

5.
Med. leg. Costa Rica ; 36(2): 17-27, sep.-dic. 2019. tab
Artigo em Espanhol | LILACS | ID: biblio-1040442

RESUMO

Resumen Introducción: El envejecimiento poblacional ha impulsado a que su abordaje se convierta en un tema prioritario a nivel mundial, sobre la cual aún existen mitos y discriminación, siendo las personas adultas mayores en privación de libertad en un sistema penitenciario, una población con mayores riesgos de exclusión y que cuentan con características neuropsicológicas que ameritan su atención. Por lo tanto, se realizó en Costa Rica un primer abordaje en el Centro de Atención Institucional Adulto Mayor desde la neuropsicología forense, para mejorar los protocolos disponibles de evaluación de la población adulta mayor. Procedimiento: Se llevó a cabo un trabajo final de graduación en formato de práctica dirigida durante 858 horas tanto de forma presencial como a distancia, en el período de abril del 2017 a abril del 2018, participando de los procesos de evaluación neuropsicológica forense, elaboración de un protocolo de evaluación neuropsicológica forense y participación en procesos psicoeducativos sobre consumo de sustancias y violencia sexual. Resultados: En total se atendieron 40 personas hombres, entre 58 y 85 años de edad. Con variables sociodemográficas y de salud como una baja escolaridad (45%), con antecedentes de trauma craneoencefálico (67%) y en su mayoría cometieron abuso sexual (55%). Se elaboró un protocolo de evaluación neuropsicológica que incluye un módulo de entrevista y observación, evaluación del estado de ánimo y evaluación del funcionamiento cognitivo.


Abstract Introduction: Population ageing has become a priority between the attention and care systems but still deals with myths and discrimination, being the older adults incarcerated in the prison system a population with a greater risk of exclusion and that have neuropsychological characteristics that need attention. Therefore, a first approach was carried out in Costa Rica in the Institutional Adult Care Center from the forensic neuropsychology, to improve the available protocols for the evaluation of the older adult population. Method: A final graduation work was carried out in a guided practice format for 858 hours both in person and remotely, in the period from April 2017 to April 2018, participating in the processes of forensic neuropsychological evaluation, preparation of a protocol of forensic neuropsychological evaluation and participation in psychoeducational processes on substance use and sexual violence. Results: In total 40 male people, between 58 and 85 years of age, were attended. With sociodemographic and health variables such as low schooling (45%), with a history of cranioencephalic trauma (67%) and most of them committed sexual abuse (55%). A neuropsychological evaluation protocol was elaborated that includes an interview and observation module, evaluation of mood and evaluation of cognitive functioning module.


Assuntos
Humanos , Idoso , Idoso de 80 Anos ou mais , Prisões , Prisioneiros , Idoso , Nível de Saúde , Costa Rica , Psicologia Forense , Neuropsicologia
6.
Phys Rev Lett ; 123(3): 031301, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31386454

RESUMO

ANAIS is a direct detection dark matter experiment aiming at the testing of the DAMA/LIBRA annual modulation result, which, for about two decades, has neither been confirmed nor ruled out by any other experiment in a model independent way. ANAIS-112, consisting of 112.5 kg of sodium iodide crystals, has been taking data at the Canfranc Underground Laboratory, Spain, since August 2017. This Letter presents the annual modulation analysis of 1.5 years of data, amounting to 157.55 kg yr. We focus on the model independent analysis searching for modulation and the validation of our sensitivity prospects. ANAIS-112 data are consistent with the null hypothesis (p values of 0.67 and 0.18 for [2-6] and [1-6] keV energy regions, respectively). The best fits for the modulation hypothesis are consistent with the absence of modulation (S_{m}=-0.0044±0.0058 cpd/kg/keV and -0.0015±0.0063 cpd/kg/keV, respectively). They are in agreement with our estimated sensitivity for the accumulated exposure, which supports our projected goal of reaching a 3σ sensitivity to the DAMA/LIBRA result in five years of data taking.

7.
Rev. chil. obstet. ginecol. (En línea) ; 84(4): 314-319, 2019. tab
Artigo em Espanhol | LILACS | ID: biblio-1058153

RESUMO

RESUMEN La rotura hepática es una complicación poco frecuente de la gestación que se asocia a preeclampsia y síndrome HELLP, aumentando la morbimortalidad materna. No hay reportados casos de esta patología en gestantes residentes en altura, a pesar de que se considera a la altura como un factor que influye en la gestación. En este artículo se reporta el caso de una gestante residente de la gran altura, la cual evidenció una rotura hepática con sangrado persistente, siendo reintervenida por cirugía de emergencia oportunamente gracias al monitoreo hemodinámico con doppler transesofágico.


ABSTRACT Hepatic rupture is a rare complication of pregnancy associated with preeclampsia and HELLP syndrome, thus increasing maternal morbidity and mortality. There are no reported cases of this condition in high-altitude dweller pregnant women, even though altitude is considered a factor that influences in pregnancy. In this article the case of a pregnant dweller at high altitude is reported, which revealed hepatic rupture with persistent bleeding, being reoperated by Emergency Surgery appropriately thanks to the hemodynamic monitoring with transesophageal Doppler


Assuntos
Humanos , Feminino , Gravidez , Adulto , Pré-Eclâmpsia/diagnóstico , Complicações na Gravidez/diagnóstico , Ruptura Espontânea/cirurgia , Complicações na Gravidez/terapia , Ultrassonografia Doppler , Monitorização Hemodinâmica , Hepatopatias/diagnóstico
8.
Eur J Neurol ; 14(10): 1079-84, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17880560

RESUMO

Histamine has a selective affinity for H3-receptors and it may specifically inhibit the neurogenic edema response involved in migraine pathophysiology. The objective of this study was to evaluate the therapeutic potential of subcutaneous administration of histamine in migraine prophylaxis, compared with oral administration of sodium valproate, in an open clinical trial. Ninety-two patients with migraine were selected under criteria established by the International Headache Society and enrolled in a 12-week double-blind controlled clinical trial to evaluate the efficacy of subcutaneous administration of histamine (1-10 ng twice a week; n = 46) compared with oral administration of sodium valproate (500 mg daily dose; n = 46). The variables studied were headache intensity, frequency, duration, analgesic intake and migraine disability assessment (MIDAS). Two-tailed Student's t- test was used to compare means and the Mann-Whitney U and anova tests were used. The data collected during the 4th, 8th and 12th weeks of treatment revealed that histamine caused a significantly greater reduction (P < 0.001) in intensity and duration of migraine attacks as well as in analgesic intake. No difference was detected in the frequency of attacks or in MIDAS. The present study provides evidence of the superior efficacy of histamine applied subcutaneously in migraine prophylaxis when compared with sodium valproate taken orally. Subcutaneously applied histamine may represent a novel and effective therapeutic alternative in resistant migraine patients.


Assuntos
Histamina/administração & dosagem , Transtornos de Enxaqueca/tratamento farmacológico , Ácido Valproico/administração & dosagem , Adolescente , Adulto , Método Duplo-Cego , Feminino , Humanos , Injeções Subcutâneas , Masculino , Pessoa de Meia-Idade , Transtornos de Enxaqueca/patologia
9.
J Virol ; 81(21): 11817-27, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17715226

RESUMO

We are still inadequately prepared for an influenza pandemic due to the lack of a vaccine effective for subtypes to which the majority of the human population has no prior immunity and which could be produced rapidly in sufficient quantities. There is therefore an urgent need to investigate novel vaccination approaches. Using a combination of genomic and traditional tools, this study compares the protective efficacy in macaques of an intrarespiratory live influenza virus vaccine produced by truncating NS1 in the human influenza A/Texas/36/91 (H1N1) virus with that of a conventional vaccine based on formalin-killed whole virus. After homologous challenge, animals in the live-vaccine group had greatly reduced viral replication and pathology in lungs and reduced upper respiratory inflammation. They also had lesser induction of innate immune pathways in lungs and of interferon-sensitive genes in bronchial epithelium. This postchallenge response contrasted with that shortly after vaccination, when more expression of interferon-sensitive genes was observed in bronchial cells from the live-vaccine group. This suggested induction of a strong innate immune response shortly after vaccination with the NS1-truncated virus, followed by greater maturity of the postchallenge immune response, as demonstrated with robust influenza virus-specific CD4+ T-cell proliferation, immunoglobulin G production, and transcriptional induction of T- and B-cell pathways in lung tissue. In conclusion, a single respiratory tract inoculation with an NS1-truncated influenza virus was effective in protecting nonhuman primates from homologous challenge. This protection was achieved in the absence of significant or long-lasting adverse effects and through induction of a robust adaptive immune response.


Assuntos
Sistema Imunitário/virologia , Orthomyxoviridae/genética , Orthomyxoviridae/metabolismo , Proteínas não Estruturais Virais/química , Animais , Biópsia , Sangue/virologia , Brônquios/patologia , Brônquios/virologia , Linfócitos T CD4-Positivos/metabolismo , Epitélio/virologia , Feminino , Regulação Viral da Expressão Gênica , Vírus da Influenza A Subtipo H1N1/metabolismo , Macaca , Masculino , Transcrição Gênica , Proteínas não Estruturais Virais/fisiologia
10.
Infect Disord Drug Targets ; 7(4): 304-17, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18220962

RESUMO

Influenza is a seasonal disease that peaks every year in the winter months. Antigenic drift of the viral surface proteins, particularly the hemagglutinin (HA), is responsible for the virus's ability to evading the host's immune system, and for the severity of the disease. Pandemic influenza arises when an influenza virus carrying a novel HA gene enters into the naive human population, resulting in excess morbidity and mortality. Three major influenza pandemics were experienced in the last century and the emergence of a new pandemic strain is considered a matter of time. Our current understanding suggests that pandemic influenza strains arise from influenza viruses circulating in the natural reservoir, although the presence of intermediate hosts is considered essential in this process. Pigs and land-based birds have been shown to play a major role in the ecology of influenza viruses by providing an environment in which influenza viruses can change their phenotype, expand their host range, and eventually transmit to humans. In recent years, a great detail of attention has been placed on understanding the epidemiological and molecular factors that can lead to interspecies transmission of influenza viruses. In this review we will discuss the ecological and molecular aspects that lead to pandemic influenza as well as the intervention strategies at our disposal that can reduce the emergence of pandemic influenza strains and/or minimize their effects.


Assuntos
Surtos de Doenças/prevenção & controle , Vírus da Influenza A/genética , Vírus da Influenza A/patogenicidade , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Orthomyxoviridae/patogenicidade , Animais , Antivirais/farmacologia , Antivirais/uso terapêutico , Doenças das Aves/epidemiologia , Doenças das Aves/transmissão , Doenças das Aves/virologia , Aves , Humanos , Vírus da Influenza A/efeitos dos fármacos , Vírus da Influenza A/imunologia , Influenza Humana/virologia , Orthomyxoviridae/genética , Orthomyxoviridae/imunologia , Suínos , Zoonoses/epidemiologia
11.
Rev Biol Trop ; 49(3-4): 1111-20, 2001.
Artigo em Espanhol | MEDLINE | ID: mdl-12189792

RESUMO

Sibon lamari, a new species of colubrid snake from northeastern Costa Rica is described on the basis of six specimens. The new form differs from the closely allied S. annulatus in color pattern, head size, subcaudal count, and number of labials bordering eye-orbit. This is the third species of Sibon, together with S. argus and S. longifrenis, possessing a green dorsal ground color in Costa Rica. Sibon lamari coexists sympatrically with S. annulatus, S. argus. S. longifrenis and S. nebulatus at the locality of Guayacán de Siquirres (Limón Province).


Assuntos
Colubridae/classificação , Animais , Região do Caribe , Colubridae/anatomia & histologia , Costa Rica , Feminino , Masculino , Especificidade da Espécie
12.
J Biol Chem ; 275(34): 26428-35, 2000 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-10833519

RESUMO

Yeast narnavirus 20 S and 23 S RNAs encode RNA-dependent RNA polymerases p91 and p104, respectively, but do not encode coat proteins. Both RNAs form ribonucleoprotein complexes with their cognate polymerases. Here we show that these complexes are not localized in mitochondria, unlike the closely related mitoviruses, which reside in these organelles. Cytoplasmic localization of these polymerases was demonstrated by immunofluorescence and by fluorescence emitted from green fluorescent protein-fused polymerases. These fusion proteins were able to form ribonucleoprotein complexes as did the wild-type polymerases. Fluorescent observations and cell fractionation experiments suggested that the polymerases were stabilized by complex formation with their viral RNA genomes. Immunoprecipitation experiments with anti-green fluorescent protein antibodies demonstrated that a single polymerase molecule binds to a single viral RNA genome in the complex. Moreover, the majority (if not all) of 20 S and 23 S RNA molecules were found to form complexes with their cognate RNA polymerases. Since these viral RNAs were not encapsidated, ribonucleoprotein complex formation with their cognate RNA polymerases appears to be their strategy to survive in the host as persistent viruses.


Assuntos
RNA Polimerases Dirigidas por DNA/metabolismo , Vírus de RNA/metabolismo , Saccharomyces cerevisiae/virologia , Northern Blotting , Citoplasma/virologia , Genoma Viral , Proteínas de Fluorescência Verde , Indicadores e Reagentes , Proteínas Luminescentes , Substâncias Macromoleculares , Mitocôndrias/virologia , Vírus de RNA/genética , Proteínas Recombinantes de Fusão/análise
13.
J Gen Virol ; 81(Pt 3): 737-42, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10675411

RESUMO

We have previously obtained four transfectant influenza A viruses containing neuraminidase (NA) genes with mutated base pairs in the conserved double-stranded RNA region of the viral promoter by using a ribonucleoprotein transfection system. Two mutant viruses (D2 and D1/2) which share a C-G-->A-U mutation at positions 11 and 12 of the 3' and 5' ends, respectively, of the NA gene, showed an approximate 10-fold reduction of NA-specific mRNA and protein levels (Fodor et al., Journal of Virology 72, 6283-6290, 1998). These viruses have now allowed us to determine the effects of decreased NA levels on virus pathogenicity. Both D2 and D1/2 viruses were highly attenuated in mice, and their replication in mouse lungs was highly compromised as compared with wild-type influenza A/WSN/33 virus. The results highlight the importance of the level of NA activity in the biological cycle and virulence of influenza viruses. Importantly, mice immunized by a single intranasal administration of 10(3) infectious units of D2 or D1/2 viruses were protected against challenge with a lethal dose of wild-type influenza virus. Attenuation of influenza viruses by mutations resulting in the decreased expression of a viral protein represents a novel strategy which could be considered for the generation of live attenuated influenza virus vaccines.


Assuntos
Vírus da Influenza A/enzimologia , Vírus da Influenza A/patogenicidade , Neuraminidase/metabolismo , Animais , Linhagem Celular , DNA Viral/genética , Feminino , Imunização , Vírus da Influenza A/genética , Vacinas contra Influenza/genética , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Neuraminidase/genética , Infecções por Orthomyxoviridae/prevenção & controle , Fenótipo , Transfecção , Vacinas Atenuadas/genética , Virulência/genética , Virulência/fisiologia , Replicação Viral/genética , Replicação Viral/fisiologia
14.
Soc Sci Med ; 49(9): 1197-213, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10501641

RESUMO

The origins of US international health endeavors are intertwined with the Progressive Era's faith in science as arbiter of humankind's secular problems. No agency better exemplifies the period's confidence in science than the Rockefeller Foundation's International Health Board (IHB), which set out to export the new public health theory and practice around the world. An examination of the IHB's hookworm program in Mexico in the 1920s demonstrates that, notwithstanding the Rockefeller Foundation's (RF) self-conscious commitment to scientific neutrality, its programs continuously engaged political criteria, exhibiting the competition, coexistence, and inseparability of the worlds of science, politics, and international health policy. Analysis of the program's quotidian decisions and larger strategies further reveals the protean quality of RF science-politics, which enabled responses to parochial and broadly-conceived needs at multiple levels. In the focus on hookworm, the selection of campaign sites, hookworm diagnosis methods, treatment procedures, definition of cure, and the assignment of responsibility for prevention, scientific and political considerations were inextricably bound. The science-politics paradox was molded by the hookworm program's constituencies in Mexico, including political leaders, health bureaucrats, physicians, business interests, public health workers, peasants, and Rockefeller officers. The multiple, often contradictory, roles of the RF's hookworm campaign are characteristic of the policy paradoxes that emerge when science is summoned to drive policy. In Mexico the campaign served as a policy cauldron through which new knowledge could be demonstrated applicable to social and political problems on many levels. The repeated pledge of scientific neutrality belied the hookworm program's inherent aim of persuading government officials, the medical community, business interests, and the populace of the value of investing in public health as a means to improve social conditions, further a medical model of health and sickness, increase economic productivity, and promote good relations between the US and Mexico.


Assuntos
Fundações/história , Política de Saúde/história , Infecções por Uncinaria/história , Cultura , História do Século XX , Infecções por Uncinaria/prevenção & controle , Humanos , México , Política , Saúde Pública/história
15.
Appl Radiat Isot ; 49(12): 1749-54, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9745702

RESUMO

The contribution of 222Rn to the background in a low background experiment with a germanium detector has been estimated. We have also checked the efficacy of a standard radon cleaning system. The cleaning reduces the radon concentration two orders of magnitude with respect to the air in the laboratory. The residual 222Rn represents at most 12.5% of the background in the low energy region, a value low enough for the purpose of our experiment. A detailed study of the radioactive background is presented.


Assuntos
Poluentes Radioativos do Ar/análise , Monitoramento de Radiação/métodos , Radônio/análise , Germânio , Monitoramento de Radiação/instrumentação , Sensibilidade e Especificidade
16.
J Biol Chem ; 273(32): 20363-71, 1998 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-9685388

RESUMO

Saccharomyces cerevisiae strains carry single-stranded RNAs called 20 S RNA and 23 S RNA. These RNAs and their double-stranded counterparts, W and T dsRNAs, have been cloned and sequenced. A few nucleotides at both ends, however, remained unknown. These RNAs do not encode coat proteins but their own RNA-dependent RNA polymerases that share a high degree of conservation to each other. The polymerases are also similar to the replicases of RNA coliphages, such as Qbeta. Here we have determined the nucleotide sequences of W and T dsRNAs at both ends using reverse transcriptase polymerase chain reaction-generated cDNA clones. We confirmed the terminal sequences by primer-extension and RNase protection experiments. Furthermore, these analyses demonstrated that W and T dsRNAs and their single-stranded RNA counterparts (i) are linear molecules, (ii) have identical nucleotide sequences at their ends, and (iii) have no poly(A) tails at their 3' ends. Both 20 S and 23 S RNAs have GGGGC at the 5' ends and the complementary 5-nucleotides sequence, GCCCC-OH, at their 3' ends. S1 and V1 secondary structure-mapping of the 3' ends of 20 S and 23 S RNAs shows the presence of a stem-loop structure that partially overlaps with the conserved 3' end sequence. Nucleotide sequences and stem-loop structures similar to those described here have been found at the 3' ends of RNA coliphages. These data, together with the similarity of the RNA-dependent RNA polymerases encoded among these RNAs and RNA coliphages, suggest that 20 S and 23 S RNAs are plus-strand single-stranded virus-like RNA replicons in yeast.


Assuntos
RNA Fúngico/química , Replicon/genética , Saccharomyces cerevisiae/genética , Clonagem Molecular , Proteínas Fúngicas/química , Dados de Sequência Molecular , Conformação de Ácido Nucleico , RNA Viral/química , RNA Polimerase Dependente de RNA/metabolismo , Ribonucleases/metabolismo , Análise de Sequência de RNA
17.
J Health Polit Policy Law ; 22(1): 73-99, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9057122

RESUMO

This study advances our understanding of the relationship between the state and the medical profession in countries where health care services are used as instruments of economic and political control. As a general argument, we maintain that the corporatist nature of the Mexican state impedes the medical profession from achieving autonomy and control over its professional activities. In contraposition to medical professions in developed societies, the nature of the Mexican profession is shaped by state policies and by its reiterated efforts to act independently of the state's tutelage. We analyze this dynamic interaction through three different historical epochs that reflect the complexity and uniqueness of the Mexican medical profession. Whatever attempts the profession has made to control the medical curriculum, the licensing process, the market, or the specific laws that affect its own field, the Mexican state has responded with measures that systematically divide and antagonize the different factions of medical associations. The result is a highly fragmented and disenfranchised medical profession with dissimilar political, professional, personal, and academic aims. In the final analysis, the interests of the corporatist Mexican state prevail over the interests of the groups, including doctors. The evisceration of the medical corps by the Mexican state results in a profession with low salaries, higher rates of unemployment, atomization in terms of political representation, and heavily co-opted medical organizations that seem to neglect the overwhelming health care needs of the Mexican people.


Assuntos
Programas Nacionais de Saúde/história , Papel do Médico , Política , Sociedades Médicas/história , Atitude Frente a Saúde , Educação Médica/tendências , Governo , Reforma dos Serviços de Saúde/história , História do Século XX , México , Programas Nacionais de Saúde/organização & administração , Autonomia Profissional , Controle Social Formal
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...