RESUMEN
Polymyxa graminis is an obligate parasite of roots and an important vector of viruses that damage cereal crops in different parts of the world. In 2011 and 2012, P. graminis was identified infecting 11 wheat root samples from three widely dispersed locations in southwest Australia. Its presence was detected by polymerase chain reaction (PCR) and confirmed by DNA sequencing of the transcribed regions of its ribosomal RNA genes (rDNA) and observing sporosori of characteristic morphology and size in stained wheat roots. Also, when soil samples were collected from two locations where P. graminis was found and wheat bait plants grown in them, P. graminis was detected in their roots by PCR. Ribosomal DNA sequences of six southwest Australian isolates were obtained from wheat roots, and one northeast Australian isolate from barley roots. When these seven P. graminis sequences were compared with others from GenBank by phylogenetic analysis, three southwest Australian isolates were classified as P. graminis f. sp. temperata (ribotypes Ia and Ib), and three as f. sp. tepida (ribotypes IIa and IIb). P. graminis f. sp. temperata and tepida both occur in temperate growing regions of other continents and are associated with transmission of soil-borne viruses to cereal crops. The P. graminis isolate from northeast Australia was sufficiently distinct from the five existing sequence groups for it to be placed into a newly proposed grouping, ribotype VI, which also included an isolate from tropical West Africa. However, when randomly collected wheat leaf samples from 39 field crops from 27 widely dispersed locations, 21 individual wheat plant samples collected from low lying areas within 21 fields at 11 locations, and wheat bait plants growing in five soil samples from two locations were tested by reverse transcription (RT)-PCR for the presence of Soil-borne wheat mosaic virus, Soil-borne cereal mosaic virus, Wheat spindle streak mosaic virus, and furoviruses in general, no virus infection was detected. These findings suggest at least three P. graminis introductions into Australia, and the occurrence of f. sp. temperata (ribotype I) and f. sp. tepida (ribotype II) suggests that, if not already present, soil-borne cereal viruses are likely to become established should they become introduced to the continent in the future.
RESUMEN
In eastern Australia, there have been several as yet unconfirmed reports of Wheat mosaic virus (WMoV) infecting wheat (3). WMoV, previously known as High plains virus (HPV), is transmitted by the wheat curl mite (WCM, Aceria tosichella). It is often found in mixed infections with Wheat streak mosaic virus (WSMV), also transmitted by WCM (2,3). WSMV was first identified in Australia in 2003 (3). In October 2012, stunted wheat plants with severe yellow leaf streaking were common in a field experiment near Corrigin in Western Australia consisting of nine wheat cultivars. These symptoms were also common in two commercial crops of wheat cv. Mace near Kulin. Leaf samples (one per plant) from each location were tested by ELISA using specific antiserum to WMoV (syn. HPV 17200, Agdia, Elkhart, IN). At the field experiment, 20 leaf samples were collected at random from each wheat plot (4 replicates) and tested individually by ELISA. WMoV incidence was 5% for cv. Yipti, 16% for cvs Emu Rock, Wyalkatchem and Mace, 22% for cvs. Corack, Fortune, Calingiri, and Magenta, and 55% for cv. Cobra. From the two commercial wheat crops, 100 leaf samples were collected at random from each and tested by ELISA. WMoV incidence was 2 and 4%. In addition, 50 leaf samples of Hordeum leporinum (barley grass) and 20 of Lolium rigidum (annual ryegrass) were collected and tested by ELISA. WMoV incidence was 2% in H. leporinum, but 0% in L. rigidum. Infected H. leporinum plants were symptomless. Symptomatic wheat leaf samples from both sites were tested by RT-PCR using WMoV specific primers designed from its RNA3 sequence (1). The PCR products (339 bp) were sequenced and lodged in GenBank (Accession Nos KC337341 and KC337342). WMoV isolates from Corrigin (WA-CG12) and Kulin (WA-KU12) had identical sequences. When the nucleic acid sequences of WA-CG12 and WA-KU12 were compared with those of the three other WMoV isolates on GenBank, they had 100% nucleotide sequence identity with a Nebraska isolate (U60141), and 99.7% identity to two United States sweet corn isolates (AY836524 and AY836525). Ten symptomatic wheat plants were collected from each location, transplanted into pots and leaf samples tested individually for WMoV and WSMV (07048, Loewe, Germany) by ELISA. All were infected with both viruses and infested with WCM. WCM-infested glumes (>10 WCM/glume) were placed on the leaf sheaths of 60 wheat plants cv. Calingiri (35 with WA-CG12 and 25 with WA-KU12) and 13 sweet corn plants cv. Snow Gold (WA-CG12 only). In addition, 20 wheat and 10 sweet corn plants were left without infested glumes to be uninoculated controls. All 60 WCM-inoculated wheat plants became stunted with severe leaf streaking. When leaf samples from each plant were tested by ELISA 18 to 30 days later, both viruses were detected. WMoV was detected in all 13 WCM-inoculated sweet corn plants and WSMV in two of them. Plants with WMoV alone initially had short chlorotic leaf streaks that subsequently combined, causing broad streaks. These are typical WMoV symptoms for sweet corn (1). No symptoms developed and no virus was detected in any of the uninoculated wheat or sweet corn control plants. The WMoV nucleotide sequence obtained from an infected sweet corn plant was identical to those of WA-CG12 and WA-KU12. To our knowledge, this is the first confirmed report of WMoV presence in Australia. References: (1) B. S. M. Lebas et al. Plant Dis. 89:1103, 2005. (2) D. Navia et al. Exp. Appl. Acarol. 59:95, 2013. (3) J. M. Skare et al. Virology 347:343, 2006.
RESUMEN
This review introduces the methods used to simulate the processes affecting dissolved oxygen (DO) in lowland rivers. The important processes are described and this provides a modelling framework to describe those processes in the context of a mass-balance model. The process equations that are introduced all require (reaction) rate parameters and a variety of common procedures for identifying those parameters are reviewed. This is important because there is a wide range of estimation techniques for many of the parameters. These different techniques elicit different estimates of the parameter value and so there is the potential for a significant uncertainty in the model's inputs and therefore in the output too. Finally, the data requirements for modelling DO in lowland rivers are summarised on the basis of modelling the processes described in this review using a mass-balance model. This is reviewed with regard to what data are available and from where they might be obtained.
RESUMEN
In this paper, a review is undertaken of the major models currently in use for describing water quality in freshwater river systems. The number of existing models is large because the various studies of water quality in rivers around the world have often resulted in the construction of new 'bespoke' models designed for the particular situation of that study. However, it is worth considering models that are already available, since an existing model, suitable for the purposes of the study, will save a great deal of work and may already have been established within regulatory and legal frameworks. The models chosen here are SIMCAT, TOMCAT, QUAL2E, QUASAR, MIKE-11 and ISIS, and the potential for each model is examined in relation to the issue of simulating dissolved oxygen (DO) in lowland rivers. These models have been developed for particular purposes and this review shows that no one model can provide all of the functionality required. Furthermore, all of the models contain assumptions and limitations that need to be understood if meaningful interpretations of the model simulations are to be made. The work is concluded with the view that it is unfair to set one model against another in terms of broad applicability, but that a model of intermediate complexity, such as QUASAR, is generally well suited to simulate DO in river systems.
RESUMEN
In response to federal intervention in 1990, Hawaii initiated a number of changes at the state's psychiatric hospital. The process of change that was undertaken by the hospital's department of nursing from 1990 through 1994 to meet federal mandates was described in an earlier article in this journal. The present study evaluated the degree to which court-ordered improvements in nursing staff at the hospital were actually achieved between 1995 and 1997. Seven quantitative measures of compliance with federal mandates were evaluated, based on the court orders. Significant improvements were found on six of the seven measures during the 30-month study period. These included increases in nursing staff as measured by (1) the number of staff and (2) full-time equivalents, as well as increases in (3) the hours of nursing care per patient, (4) the number of staff per patient on each shift, and (5) the percent of RNs per shift. Use of agency personnel decreased significantly, as ordered, but overtime use increased significantly, contrary to court orders.
Asunto(s)
Trastornos Mentales/enfermería , Personal de Enfermería en Hospital/legislación & jurisprudencia , Enfermería Psiquiátrica/legislación & jurisprudencia , Garantía de la Calidad de Atención de Salud/legislación & jurisprudencia , Hawaii , Hospitales Psiquiátricos/legislación & jurisprudencia , Hospitales Provinciales/legislación & jurisprudencia , HumanosRESUMEN
BACKGROUND: Osteonecrosis (avascular necrosis) has been infrequently reported in HIV-infected patients. It is not known whether HIV itself is an independent risk factor for osteonecrosis. METHODS: We identified 25 patients with osteonecrosis from 1984 to 1999 from a large county teaching hospital and two large practices in Dallas County that specialize in HIV-disease related therapy. A retrospective chart review was performed to evaluate potential risk factors for osteonecrosis. Each case was matched with two controls for HIV positive status and date of osteonecrosis diagnosis. RESULTS: In the study, 22 of 25 (88%) case patients had at least one osteonecrosis risk factor compared with 24 of 50 (48%) controls, p =.003. The most common osteonecrosis risk factors were hyperlipidemia (32%), alcoholism (28%), pancreatitis (16%), corticosteroids (12%), and hypercoaguability (12%). Of the cases, 12% were idiopathic. Multiple joints were involved in 72% of cases. Four of the case patients compared with none of the controls received megesterol acetate before the diagnosis of osteonecrosis, p =.01. No significant differences were found between cases and controls with respect to liver function tests, testosterone levels, triglyceride levels, cholesterol levels, or CD4 cell counts. Saquinavir was independently associated with osteonecrosis, p <.05. However, no differences in overall use of protease inhibitors among cases and controls were noted: 79% versus 76%, respectively. CONCLUSIONS: The increased incidence of osteonecrosis in HIV/AIDS may be due to an increased frequency of risk factors previously associated with osteonecrosis such as hyperlipidemia, corticosteroid use, alcohol abuse, and hypercoaguability. Use of protease inhibitors was not independently associated with osteonecrosis.
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Infecciones por VIH/complicaciones , Osteonecrosis/complicaciones , Osteonecrosis/epidemiología , Adulto , Recuento de Linfocito CD4 , Estudios de Casos y Controles , Colesterol/análisis , Femenino , Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/uso terapéutico , Humanos , Incidencia , Masculino , Acetato de Megestrol/farmacología , Osteonecrosis/inducido químicamente , Osteonecrosis/inmunología , Estudios Retrospectivos , Factores de Riesgo , Saquinavir/uso terapéutico , Testosterona/análisis , Triglicéridos/análisisRESUMEN
Dopamine (DA) neurons in the ventral tegmental area and substantia nigra pars compacta were induced to fire in bursts with application of N-methyl-D-aspartate (NMDA, 20 microM) and apamin (100 nM) while recording intracellularly in the rat brain slice. L-Arginine (300 microM), a substrate for nitric oxide (NO) production, increased both the number of spikes per burst and the magnitude of interburst hyperpolarizations. Nitric oxide synthase inhibitors N-nitro-L-arginine methyl ester (L-NAME, 100 microM), N-nitro-L-arginine, and 7-nitroindazole inhibited NMDA-induced burst firing by reducing the number of spikes per burst. Moreover, L-arginine (100 microM) reversed the inhibition of burst firing produced by L-NAME. These findings suggest that NO facilitates NMDA-induced burst firing in DA neurons.
Asunto(s)
Dopamina/metabolismo , Mesencéfalo/fisiología , N-Metilaspartato/farmacología , Neuronas/fisiología , Óxido Nítrico/fisiología , Animales , Apamina/farmacología , Arginina/farmacología , Sinergismo Farmacológico , Electrofisiología , Inhibidores Enzimáticos/farmacología , Técnicas In Vitro , Indazoles/farmacología , Masculino , Mesencéfalo/citología , Mesencéfalo/efectos de los fármacos , Mesencéfalo/metabolismo , NG-Nitroarginina Metil Éster/farmacología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Nitroarginina/farmacología , Ratas , Ratas Sprague-DawleyRESUMEN
Recent advances in ultrasound technology, such as the use of high-frequency linear transducers, color flow Doppler, and computer-enhanced imaging, have improved the diagnostic utility of ultrasound. The following retrospective study was performed to evaluate the efficacy of sonographic signs of malignancy and to compare sonography to mammography in 157 patients with palpable, biopsy-proven breast carcinomas. The mammogram reports and sonograms were all reviewed. The grade of each mammogram was recorded using the American College of Radiology mammogram grading scale. All sonograms were reviewed and assigned a score using an adaptation of this scale. Of 157 lesions, 121 were read as suspicious or probable malignancies on mammogram. Thirty-three lesions were read as benign or normal on mammogram. Three patients did not receive mammograms. All 157 lesions were read as either suspicious or probably malignant on ultrasound. Using the 16 described criteria, high-definition sonography complements mammography and appears to be a sensitive modality in the evaluation of palpable biopsy-proven breast malignancies. The diagnostic utility of ultrasound will likely be most important in the evaluation of nonpalpable breast masses; however, a prospective randomized trial will need to be performed.
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Neoplasias de la Mama/diagnóstico por imagen , Ultrasonografía Mamaria , Biopsia , Mama/patología , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , Carcinoma in Situ/diagnóstico por imagen , Carcinoma in Situ/patología , Carcinoma Ductal de Mama/diagnóstico por imagen , Carcinoma Ductal de Mama/patología , Carcinoma Ductal de Mama/cirugía , Carcinoma Lobular/diagnóstico por imagen , Carcinoma Lobular/patología , Carcinoma Lobular/cirugía , Femenino , Humanos , Metástasis Linfática , Mamografía , Estadificación de Neoplasias , Estudios Retrospectivos , Sensibilidad y EspecificidadRESUMEN
Effects of L-arginine in the nervous system are often attributed to nitric oxide. Using whole-cell patch pipettes to record membrane currents in voltage-clamp from dopamine neurons in the rat midbrain slice, the present studies found that L-arginine potentiates GABA-dependent membrane currents via a nitric oxide-independent mechanism. L-Arginine (0.3-10 mM) increased the peak amplitude, half-width duration and time constant of decay of GABA(B) receptor-mediated inhibitory postsynaptic currents in a concentration-dependent manner. In the presence of CGP 35348 (300 microM), a GABA(B) receptor antagonist, L-arginine also prolonged the duration of inhibitory postsynaptic currents mediated by GABA(A) receptors, but their amplitudes were reduced. L-Arginine (10 mM) also evoked 17+/-3 pA of outward current (at -60 mV) which was significantly increased in the presence of exogenous GABA (100 microM). Pressure-ejection of GABA from micropipettes produced outward currents mediated by GABA(B) receptors (recorded in bicuculline) or GABA(A) receptors (recorded in CGP 35348); both types of receptor-mediated currents were increased by L-arginine (10 mM). In contrast, outward currents evoked by baclofen, a GABA(B) receptor agonist, were not potentiated by L-arginine. The GABA transport inhibitors NO 711 (1 microM) and nipecotic acid (1 mM) significantly increased the half-width duration and time-constant of decay of GABA(B)-mediated inhibitory postsynaptic currents, thus mimicking effects of L-arginine. However, nitric oxide donors failed to mimic effects of L-arginine on GABA(B) inhibitory postsynaptic currents, and inhibitors of nitric oxide synthesis failed to selectively block the action of L-arginine. These findings suggest that L-arginine potentiates GABA synaptic transmission by a nitric oxide-independent mechanism. Similarities between effects of L-arginine, NO 711 and nipecotic acid suggest that L-arginine inhibits a GABA transporter.
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Arginina/farmacología , Dopamina/metabolismo , Neuronas/efectos de los fármacos , Óxido Nítrico/farmacología , Receptores de GABA/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Masculino , Ratas , Ratas Sprague-Dawley , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
We stably expressed a rat D3 receptor cDNA in C6 glioma cells (C6-D3 cells), quantifying receptor expression with the radioligands [125I]epidepride (KD = 0.1 nM) and [3H]spiperone (KD = 0.7 nM). As reported previously for D2 receptors, quinpirole induced a 9-16% increase in the rate of extracellular acidification by C6-D3 cells. The acidification was inhibited by epidepride and by the Na+/H+ antiporter inhibitors, amiloride and methylisobutylamiloride, but pertussis toxin treatment had no effect on quinpirole-induced extracellular acidification. These data suggest that D3 receptor stimulation of Na+/H+ exchange in C6 glioma cells is not mediated by the pertussis toxin-sensitive G proteins, Gi or G(o). Overnight treatment of C6-D3 cells with N-propylnorapomorphine, dopamine, or quinpirole resulted in large concentration-dependent increases (up to 500%) in the density of D3 receptors on membranes prepared from the cells. Antagonists had smaller, variable effects on the density of D3 receptors in C6-D3 cells, except for domperidone, which significantly increased the density of D3 receptors. Treatment with pertussis toxin had no effect on the agonist-induced receptor up-regulation, indicating that an interaction with pertussis toxin-sensitive G proteins was not required. Densitometry analysis of Northern blots of RNA prepared from C6-D3 cells showed no significant N-propylnorapomorphine-induced increase in D3 receptor message. Treatment with cycloheximide, however, completely prevented receptor up-regulation by N-propylnorapomorphine. Pretreatment of C6-D2 cells with 10 microM DA resulted in a substantial heterologous sensitization, in which isoproterenol-stimulated adenylyl cyclase activity was enhanced more than twofold.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Glioma/genética , Receptores Dopaminérgicos/efectos de los fármacos , Receptores Dopaminérgicos/fisiología , Transducción de Señal/fisiología , Amilorida/farmacología , Animales , ADN Complementario , Relación Dosis-Respuesta a Droga , Expresión Génica , Ensayo de Unión Radioligante , Ratas , Ratas Endogámicas , Recombinación Genética , Factores de TiempoRESUMEN
A photoreactive azido analog of the trypanocide ethidium bromide, 3-amino-8-azido-5-ethyl-6-phenylphenanthridinium chloride, attached covalently to calf thymus DNA (CT DNA) by photoaffinity labeling, was used to generate antibodies for the drug analog. The specificity of the antiserum was tested using enzyme-linked immunoadsorbant assays (ELISA) against immobilized antigen (photoaffinity labeled DNA) and by both the avidin-biotin peroxidase reaction and indirect immunofluorescence performed on smears of drug treated trypanosomes. The reaction of the antiserum with the covalently bound drug adduct was diminished effectively by prior incubation with an excess of ethidium monoazide, ethidium diazide, and ethidium bromide, and to a lesser extent by the DNA-ethidium complex, the diazide-DNA or RNA adduct, and the monoazide-RNA adduct. DNA which had been photoaffinity labeled with either the propidium or the acridine moiety did not react. The antiserum recognition of DNA photoaffinity labeled with ethidium monoazide was based on the substituted phenanthridinium ring system of the parent ethidium, as evidenced by competition binding studies involving the free monoazido analog (EA1), the diazido analog (EA2), and the parent compound, ethidium bromide (EB). This approach and the sensitivity it provides should prove useful for identifying the distribution and fate of covalently bound drugs resulting from antiparasitic drug treatment, and for studying their roles in antiparasitic action.
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ADN/metabolismo , Etidio/metabolismo , Trypanosoma brucei brucei/metabolismo , Marcadores de Afinidad , Animales , Anticuerpos , Especificidad de Anticuerpos , Bovinos , Ensayo de Inmunoadsorción Enzimática/métodos , Etidio/inmunología , Técnica del Anticuerpo Fluorescente , Técnicas para Inmunoenzimas , Sensibilidad y EspecificidadRESUMEN
Four dopamine D2 receptor mutants were constructed, in each of which an alanine residue was substituted for one of four conserved serine residues, i.e., Ser-193, Ser-194, Ser-197, and Ser-391. Wild-type and mutant receptors were expressed transiently in COS-7 cells and stably in C6 glioma cells for analysis of ligand-receptor interactions. In radioligand binding assays, the affinity of D2 receptors for dopamine was decreased 50-fold by substitution of alanine for Ser-193, implicating this residue in the binding of dopamine. Each mutant had smaller decreases in affinity for one or more of the ligands tested, with no apparent relationship between the class of ligand and the pattern of mutation-induced changes in affinity, except that the potency of agonists was decreased by substitution for Ser-193. The potency of dopamine for inhibition of adenylyl cyclase was reduced substantially by substitution of alanine for Ser-193 or Ser-197. Mutation of Ser-194 led to a complete loss of efficacy for dopamine and p-tyramine, which would be consistent with an interaction between Ser-194 and the p-hydroxyl substituent of dopamine that is necessary for activation of the receptors to occur. Because mutation of the corresponding residues of beta 2-adrenergic receptors has very different consequences, we conclude that although the position of these serine residues is highly conserved among catecholamine receptors, and the residues as a group are important in ligand binding and activation of receptors by agonists, the function of each of the residues considered separately varies among catecholamine receptors.
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Receptores Dopaminérgicos/fisiología , Serina/fisiología , Inhibidores de Adenilato Ciclasa , Alanina/análisis , Alanina/metabolismo , Alanina/fisiología , Animales , Secuencia de Bases , Benzamidas/metabolismo , Línea Celular , Glioma/metabolismo , Glioma/patología , Glioma/ultraestructura , Immunoblotting , Radioisótopos de Yodo , Ligandos , Datos de Secuencia Molecular , Mutación/genética , Hibridación de Ácido Nucleico , Pirrolidinas/metabolismo , ARN Mensajero/análisis , ARN Mensajero/genética , Ensayo de Unión Radioligante , Receptores Adrenérgicos beta/genética , Receptores Adrenérgicos beta/metabolismo , Receptores Adrenérgicos beta/fisiología , Receptores Dopaminérgicos/genética , Receptores Dopaminérgicos/metabolismo , Receptores de Dopamina D2 , Serina/análisis , Serina/metabolismo , Células Tumorales Cultivadas/metabolismo , Células Tumorales Cultivadas/patología , Células Tumorales Cultivadas/ultraestructuraRESUMEN
An aspartate residue corresponding to aspartate-80 of dopamine D2 receptors is strictly conserved among receptors that couple to guanine nucleotide-binding proteins. Mutation of this residue alters the function of several classes of neurotransmitter receptors. Dopamine D2 receptors couple to the guanine nucleotide-binding protein Gi to inhibit adenylyl cyclase (ATP-pyrophosphate-lyase, cyclizing; EC 4.6.1.1). Like other Gi-coupled receptors, the binding of agonists and some antagonists to D2 receptors is sensitive to pH and sodium. In the present report, we demonstrate that substitution of an alanine or glutamate residue for aspartate-80 severely impairs inhibition of adenylyl cyclase by D2 receptors and also abolishes or decreases the regulation of the affinity of D2 receptors for agonists and substituted benzamide antagonists by sodium and pH. Our data support the hypothesis that the conformation of D2 receptors is maintained by interactions of monovalent cations with aspartate-80. The regulation of D2 receptors by this interaction has important consequences for the affinity of D2 receptors for ligands and for signal transduction by D2 receptors.
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Inhibidores de Adenilato Ciclasa , Ácido Aspártico/fisiología , Receptores Dopaminérgicos/fisiología , Secuencia de Aminoácidos , Benzamidas/metabolismo , Etilmaleimida/farmacología , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Mutación , Conformación Proteica , Pirrolidinas/metabolismo , Ensayo de Unión Radioligante , Receptores Dopaminérgicos/análisis , Receptores de Dopamina D2 , Sodio/farmacología , Relación Estructura-ActividadRESUMEN
We describe a boy with severe hypotonia and minor facial anomalies with a terminal deletion of chromosome 2q (46,XY,del(2)(q37)). Comparison with previous cases in the literature indicates that this particular deletion results in infantile hypotonia, developmental delay, and minor craniofacial anomalies including frontal bossing and micrognathia. The absence of true malformations and few minor anomalies in this patient suggests that indications for obtaining a chromosome analysis from neurologically impaired individuals need to be reevaluated.
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Anomalías Múltiples/genética , Aberraciones Cromosómicas , Deleción Cromosómica , Trastornos de los Cromosomas , Cromosomas Humanos Par 2 , Hipotonía Muscular/genética , Anomalías Múltiples/patología , Anomalías Múltiples/fisiopatología , Aberraciones Cromosómicas/patología , Aberraciones Cromosómicas/fisiopatología , Bandeo Cromosómico , Músculos Faciales/fisiopatología , Trastornos del Crecimiento/genética , Trastornos del Crecimiento/patología , Trastornos del Crecimiento/fisiopatología , Humanos , Lactante , Discapacidad Intelectual/genética , Cariotipificación , Masculino , Hipotonía Muscular/patología , FenotipoRESUMEN
To identify the in vivo targets of the trypanocide, ethidium bromide, the fluorescent staining of T. brucei was examined for a series of ethidium analogs using fluorescence microscopy. Determination of the biological targets for most drugs is limited by the reversible nature of their interactions. To overcome this limitation, photoaffinity (azido) analogs of ethidium, which are capable of covalent attachment with photoactivation, were used to identify the ethidium binding sites within the parasites. Two of these compounds, when covalently attached, demonstrated an enhancement of fluorescent staining and were selective for the kinetoplast at low drug concentrations. These compounds were also those found previously to have the highest trypanocidal activity. Propidium, a phenanthridinium analog identical to ethidium except for a larger, more ionic substitution at R5, showed more nonspecific binding as determined by its general staining of the cytoplasm.
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Etidio/análogos & derivados , Etidio/metabolismo , Trypanosoma brucei brucei/citología , Marcadores de Afinidad , Animales , Microscopía Fluorescente/métodos , Ratas , Relación Estructura-Actividad , Fracciones Subcelulares/ultraestructuraRESUMEN
The effect of metabolic activation on the mutagenic potential of some phenanthridinium compounds was examined in Salmonella typhimurium strains TA1538 and TA1978 . All of the compounds tested were mutagenic in TA1538, a DNA excision-repair-deficient strain, when metabolizing enzymes were included in the assay. Reversions were not detected when these compounds were examined under the same conditions in TA1978 , the isogenic strain of TA1538 proficient in DNA repair. The mutagenic activity of an azido analog of propidium iodide was also examined using photoactivation and enzymatic activation, and with both conditions, reversions were observed in TA1538 but not in TA1978 . Furthermore, the ranking of mutagenic activity of propidium azide relative to ethidium azide analogs was comparable for both types of activation. The evidence from several studies suggests that the structural requirements for mutagenic activity for this series of phenanthridinium compounds appear to be the same whether mutagenesis is induced via photoactivation or metabolic activation. The interaction with DNA resulting in covalent alteration of the DNA is implicated as the mutagenic mechanism whether the active species is generated by metabolic- or photo-activation.
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Mutación/efectos de los fármacos , Fenantridinas/toxicidad , Marcadores de Afinidad , Animales , Biotransformación , Fenómenos Químicos , Química , ADN/metabolismo , Masculino , Microsomas Hepáticos/metabolismo , Fenantridinas/metabolismo , Ratas , Salmonella typhimurium/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
The fluorescent compounds ethidium monoazide and ethidium bromide were found to react intensely with nucleic acids of fixed, paraffin embedded tissues of rat and mouse. For routine staining, 10(-5) M solutions of ethidium bromide and its monoazide analogue were virtually identical in their reactions. Fresh frozen sections of the tissues reacted in the same manner as fixed, paraffin embedded samples. Fluorescence of DNA and RNA in rat pancreas could be selectively abolished by taking advantage of the greater sensitivity of RNA to acid hydrolysis. Hydrolysis in aqueous solutions (1 N HCl at 55-60 C) abolished RNA fluorescence in 5 min, whereas 20 min or longer were required to destroy DNA fluorescence. DNA fluorescence was selectively abolished by 3 hr in 0.1 N HCl in anhydrous methanol while the RNA remained unaffected. Rat pancreas stained with the 10(-5) M ethidium compounds below pH 5.0 showed reduced RNA fluorescence, but the DNA continued to fluoresce brightly at pH 0.6. Reducing the pH of the staining solution to pH 1.0, therefore, was an additional method of selectively abolishing RNA fluorescence. Ethidium solutions in 5.0 M NaCl at pH 5.0 had little effect on DNA or RNA fluorescence. This new method of examining nucleic acids in fixed tissue samples opens new approaches to the histochemistry of these substances. The method also offers new possibilities for the study of mutagenic drug-DNA interactions.
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Azidas , Etidio , Histocitoquímica/métodos , Animales , Núcleo Celular/análisis , Citoplasma/análisis , ADN/análisis , Fluorescencia , Concentración de Iones de Hidrógeno , Ratones , Páncreas/análisis , ARN/análisis , RatasRESUMEN
Benoxaprofen [2-(4-chlorophenyl)-alpha-methyl-5-benzoxazole acetic acid], a novel anti-inflammatory compound, is also an orally-active anti-allergic compound in animals. It reduced the anaphylactic release of mediators, particularly slow-reacting substance of anaphylaxis (SRS-A), from both in vitro and in vivo animal models. Benoxaprofen marginally antagonized the activity of histamine on the guinea pig ileum, but not of SRS-A, at concentrations which inhibited the release of SRS-A.