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1.
J Sports Sci ; 37(12): 1365-1374, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30583702

RESUMEN

Evidence supporting use of the Functional Movement Screen (FMSTM) to identify athletes' risk of injury is equivocal. Furthermore, few studies account for exposure to risk during analysis. This study investigated the association of FMSTM performance with incidence and burden of match-injuries in adult community rugby players. 277 players performed the FMSTM during pre-season and in-season time-loss injuries and match exposure were recorded. The associations between FMSTM score, pain, and movement-pattern asymmetries with match-injury incidence (≥8-days time-loss/1000hours), severe match-injury incidence (>28-days time-loss/1000hours), and match-injury burden (total time-loss days/1000hours for ≥8-days match-injuries) were analysed using Poisson regression. Multivariate analysis indicated players with pain and movement-pattern asymmetry during pre-season had 2.9 times higher severe match-injury incidence (RR, 90%CI = 2.9, 0.9-9.7) and match-injury burden (RR, 90%CI = 2.9, 1.3-6.6). Players with a typically low FMSTM score (mean - 1SD threshold) were estimated to have a 50% greater match-injury burden compared to players with a typically high FMSTM score (mean + 1SD threshold) as match-injury burden was 10% lower per 1-unit increase in FMSTM score. As the strongest association with injury outcome was found for players with pain and asymmetry, when implementing the FMSTM it is advisable to prioritise these players for further assessment and subsequent treatment.


Asunto(s)
Traumatismos en Atletas/epidemiología , Fútbol Americano/lesiones , Movimiento , Traumatismos en Atletas/diagnóstico , Humanos , Incidencia , Masculino , Tamizaje Masivo , Análisis Multivariante , Dolor/epidemiología , Estudios Prospectivos , Factores de Riesgo
2.
Int J Sports Med ; 37(8): 659-64, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27176887

RESUMEN

The aim of this study was to describe the incidence, severity and type of shoulder injuries resulting from match play in adult community rugby union between 2009-2013. A total of 254 time-loss shoulder injuries were reported, an overall incidence of 2.2 per 1 000 h (95% CI: 1.9 to 2.4), and a mean injury severity of 9.5 weeks missed (95% CI: 8.2 to 10.8). The semi-professional group had an incidence of 2.8 injuries per 1 000 h (95% CI: 2.2 to 3.5), which was higher than the recreational group at 1.8 injuries per 1 000 h (95% CI: 1.4 to 2.2, p=0.004). The incidence of acromioclavicular joint injury for semi-professional players was 1.2 per 1 000 h (95% CI: 0.8 to 1.6); which was significantly higher than the incidence of this injury type in recreational players (0.5 per 1 000 h 95% CI: 0.3 to 0.7, p=0.002). Overall, back row players sustained the highest incidence of all shoulder injuries for a given playing position, 2.9 injuries per 1 000 h (95% CI: 2.2 to 3.6). The tackle was the main event associated with injury. Injury prevention programs and coaching strategies that consider tackle technique and physical conditioning of the shoulder region are therefore considered important.


Asunto(s)
Traumatismos en Atletas/epidemiología , Fútbol Americano/lesiones , Lesiones del Hombro/epidemiología , Articulación Acromioclavicular/lesiones , Inglaterra , Humanos , Incidencia , Recurrencia
3.
J Evol Biol ; 27(1): 116-32, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24330186

RESUMEN

Rapid geographic range expansions can have dramatic effects on the distribution of genetic diversity, both within and among populations. Based on field records collected over the past two decades in Western Europe, we report on the rapid geographic range expansion in Colletes hederae, a solitary bee species. To characterize how this expansion shaped the distribution of genetic diversity within and among populations, we performed a genetic analysis based on the sequencing of three nuclear loci (RNAp, CAD and WgL). We then simulated the evolution of DNA sequences under a spatially explicit model of coalescence to compare different hypotheses regarding the mode of colonization associated with this rapid expansion and to identify those that are most consistent with the observed molecular data. Our genetic analyses indicate that the range expansion was not associated with an important reduction in genetic diversity, even in the most recently colonized area in the United Kingdom. Moreover, little genetic differentiation was observed among populations. Our comparative analysis of simulated data sets indicates that the observed genetic data are more consistent with a demographic scenario involving relatively high migration rates than with a scenario based on a high reproduction rate associated with few migrants. In the light of these results, we discuss the factors that might have contributed to the rapid geographic range expansion of this pollen-specialist solitary bee species across Western Europe.


Asunto(s)
Abejas/genética , Animales , Secuencia de Bases , Europa (Continente) , Evolución Molecular , Femenino , Variación Genética , Masculino , Datos de Secuencia Molecular , Filogeografía
4.
Science ; 274(5284): 88-90, 1996 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-8810252

RESUMEN

Thermoregulation of the thorax allows endothermic insects to achieve power outputs during flight that are among the highest in the animal kingdom. Flying endothermic insects, including the honeybee Apis mellifera, are believed to thermoregulate almost exclusively by varying heat loss. Here it is shown that a rise in air temperature from 20 degrees to 40 degrees C causes large decreases in metabolic heat production and wing-beat frequency in honeybees during hovering, agitated, or loaded flight. Thus, variation in heat production may be the primary mechanism for achieving thermal stability in flying honeybees, and this mechanism may occur commonly in endothermic insects.


Asunto(s)
Abejas/fisiología , Regulación de la Temperatura Corporal/fisiología , Vuelo Animal/fisiología , Animales , Abejas/metabolismo , Metabolismo Energético , Homeostasis , Temperatura , Alas de Animales/fisiología
5.
Br J Pharmacol ; 151(8): 1352-67, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17592503

RESUMEN

BACKGROUND AND PURPOSE: Several studies using radioligand binding assays, have shown that measurement of thermodynamic parameters can allow discrimination of agonists and antagonists (Weiland et al., 1979; Borea et al., 1996a). Here we investigate whether agonists and antagonists can be thermodynamically discriminated at CCK(2) receptors in rat cerebral cortex. EXPERIMENTAL APPROACH: The pK(L) of [(3)H]-JB93182 in rat cerebral cortex membranes was determined at 4, 12, 21 and 37 degrees C in 50 mM Tris-HCl buffer (buffer B pH 6.96; containing 0.089 mM bacitracin). pK(I) values of ligands of diverse chemical structure and with differing intrinsic activity (alpha), as defined by the lumen-perfused rat and mouse stomach bioassays, were determined in buffer B at 4, 12, 21 and 37 degrees C. KEY RESULTS: [(3)H]-JB93182 labelled a homogeneous population of receptors in rat cerebral cortex at 4, 12, 21 and 37 degrees C and the pK(L) and B(max) were not altered by incubation temperature. [(3)H]-JB93182 binding reached equilibrium after 10, 50, 90 and 220 min at 37, 21, 12 and 4 degrees C, respectively. pK(I) values for R-L-365,260, R-L-740,093, YM220, PD134,308 and JB95008 were higher at 4 degrees C than at 37 degrees C. There was no effect of temperature on pK(I) values for pentagastrin, CCK-8S, S-L-365,260, YM022, PD140,376 and JB93242. CONCLUSIONS AND IMPLICATIONS: CCK(2) receptor agonists and antagonists at rat CCK(2) receptors cannot be discriminated by thermodynamic analysis using [(3)H]-JB93182 as the radioligand.


Asunto(s)
Ensayo de Unión Radioligante/métodos , Receptor de Colecistoquinina B/agonistas , Receptor de Colecistoquinina B/antagonistas & inhibidores , Termodinámica , Animales , Unión Competitiva , Bioensayo , Corteza Cerebral , Indoles/metabolismo , Ligandos , Masculino , Ratones , Radiofármacos , Ratas , Ratas Wistar , Temperatura
6.
J Med Chem ; 44(8): 1125-33, 2001 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-11312913

RESUMEN

In the course of structural explorations around a series of potent CCK2 receptor antagonists, it was noted that simple N-methylation of the indolic N-H in the parent molecule gave rise to behavior in vivo that was consistent with the compound acting as an agonist. Exploration in vitro confirmed this property, and it was shown that the agonist action could be blocked by the reference CCK2 receptor antagonist, L-365,260. Further examples of this type of modification were explored, and a common theme with regard to agonist behavior was uncovered. Some molecular modeling is also presented in an attempt to throw light on the nature of the ligand receptor interactions that may be giving rise to the differing properties of these, apparently, structurally similar molecules.


Asunto(s)
Adamantano/análogos & derivados , Adamantano/síntesis química , Indoles/síntesis química , Receptores de Colecistoquinina/agonistas , Adamantano/química , Adamantano/farmacología , Animales , Benzodiazepinonas/farmacología , Unión Competitiva , Corteza Cerebral/metabolismo , Técnicas In Vitro , Indoles/química , Indoles/farmacología , Ligandos , Ratones , Modelos Moleculares , Pentagastrina/farmacología , Compuestos de Fenilurea/farmacología , Ensayo de Unión Radioligante , Ratas , Receptor de Colecistoquinina B , Receptores de Colecistoquinina/antagonistas & inhibidores , Receptores de Colecistoquinina/metabolismo , Estereoisomerismo , Estómago/efectos de los fármacos
7.
Br J Pharmacol ; 118(7): 1717-26, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8842437

RESUMEN

1. For several years, we have used the cholecystokinin (CCK)B/gastrin receptor selective antagonist, L-365,260, as a reference compound in a variety of studies in CCKB/gastrin receptor radioligand binding assays. Here, we have analysed the competition curve data sets obtained between L-365,260 and [125I]-BH-CCK8S in guinea-pig gastric gland and mouse and rat cerebral cortex preparations. 2. Competition curves obtained for L-365,260 in the mouse cortex assay were not different from rectangular hyperbolae (slope = 1.01 +/- 0.02) implying the presence of a single population of binding sites (pKI = 8.41 +/- 0.01; data from 47 experiments, slope constrained to unity). However, in the rat cortex and guinea-pig gastric gland assays, the mean slope of the competition curves was significantly less than one and the mean apparent pKI significantly lower than that obtained in the mouse cortex (slope = 0.85 +/- 0.03, 0.90 +/- 0.03; apparent pKI = 7.98 +/- 0.05, 8.07 +/- 0.05; 48 and 45 experiments, in rat and guinea-pig, respectively). The distribution of the individual pKI and slope estimates of the competition curves in these two assays was consistent with expectations for the variable expression (in terms of absolute number and proportion) of two binding sites. The two sites were characterized by pKI values for L-365,260 of 8.50 +/- 0.04 and 8.48 +/- 0.04 for the high affinity site and 7.32 +/- 0.04 and 7.22 +/- 0.06 for the low affinity site in guinea-pig and rat, respectively. 3. The affinity estimates for L-365,260, although obtained on different tissues, are consistent with data obtained from the analysis of L-365,260 antagonism of pentagastrin-stimulated responses in mouse and rat stomach (acid secretion) and guinea-pig gastric muscle (isotonic contraction) assays. To this extent, these data suggest the existence of two CCKB/gastrin receptor subtypes.


Asunto(s)
Benzodiazepinonas/farmacología , Compuestos de Fenilurea , Receptores de Colecistoquinina/antagonistas & inhibidores , Animales , Unión Competitiva/efectos de los fármacos , Corteza Cerebral/citología , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/metabolismo , Colecistoquinina/metabolismo , Mucosa Gástrica/citología , Mucosa Gástrica/efectos de los fármacos , Cobayas , Técnicas In Vitro , Radioisótopos de Yodo , Masculino , Ratones , Ensayo de Unión Radioligante , Ratas , Ratas Wistar , Succinimidas
8.
Br J Pharmacol ; 119(7): 1401-10, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8968549

RESUMEN

1. The CCKB/gastrin receptors mediating pentagastrin stimulation of gastric acid secretion by histamine release and by direct stimulation of oxyntic cells have been characterized in the immature rat isolated stomach assay. This was achieved by estimating antagonist affinity values for competitive antagonists from three distinct chemical classes (L-365,260, PD134,308 and JB93190) in the absence and presence of a high concentration of the histamine H2-receptor antagonist, famotidine (30 microM). 2. Pentagastrin produced concentration-dependent stimulation of gastric acid secretion in the absence and presence of famotidine. Famotidine depressed the maximum secretory response to pentagastrin although the degree of depression varied between experimental replicates (25-60%). This variation was attributed to the histamine-release mediated component of acid secretion, as judged by the consistency of the maximum responses obtained in the presence, but not absence, of famotidine. 3. All three CCKB/gastrin receptor antagonists behaved as surmountable antagonists in the absence and presence of famotidine. JB93190 (pKB approximately 9.1, approximately 8.9, in the absence and presence of famotidine, respectively) was approximately 30 fold more potent than either L-365,260 (pKB approximately 7.4, approximately 7.1) or PD134,308 (pKB approximately 7.6, approximately 7.4). 4. It was assumed that the famotidine treatment converted pentagastrin-stimulated acid secretion from a combination of an indirect action due to the release of histamine and a direct action on the oxyntic cell to solely a direct action on the oxyntic cell. A simple mathematical model of this two-receptor system was developed. The direct and indirect components were assumed to sum to produce the total response to pentagastrin obtained in the absence of famotidine. It was found that this model could account quantitatively for the behaviour of the three antagonists without invoking a difference in antagonist affinity for the CCKB/gastrin receptors mediating the direct and indirect actions of pentagastrin. However, a conclusion of receptor homogeneity has to be qualified because the model was also used to generate simulations which indicated that the analysis could only detect antagonist affinity differences of greater than one log-unit between enterochromaffin-like (ECL) and oxyntic cell CCKB/gastrin receptor populations.


Asunto(s)
Ácido Gástrico/metabolismo , Mucosa Gástrica/metabolismo , Histamina/farmacología , Pentagastrina/farmacología , Receptores de Colecistoquinina/efectos de los fármacos , Animales , Unión Competitiva/efectos de los fármacos , Células Enterocromafines/efectos de los fármacos , Células Enterocromafines/metabolismo , Famotidina/farmacología , Mucosa Gástrica/efectos de los fármacos , Antagonistas de los Receptores H2 de la Histamina/farmacología , Técnicas In Vitro , Cinética , Modelos Biológicos , Ratas , Ratas Wistar , Receptores de Colecistoquinina/antagonistas & inhibidores , Estimulación Química
9.
Br J Pharmacol ; 118(7): 1779-89, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8842444

RESUMEN

1. Since L-365,260 was first described as a selective antagonist at cholecystokinin (CCK)B/gastrin receptors, we have used it periodically as a reference compound in isolated tissue assays of guinea-pig gastric muscle and lumen-perfused stomachs from mouse and immature rat. L-365,260 behaved as a surmountable antagonist and produced parallel rightward shifts of pentagastrin concentration-effect curves' in each of the replicate experiments. The experiments were performed by several different experimenters in the same laboratories over a five year period. 2. In the isolated, lumen-perfused, immature rat stomach assay, L-365,260 behaved as a simple competitive antagonist (Schild plot slope = 1.00 +/- 0.10, pKB = 7.54 +/- 0.03 from a global analysis of the data) acting at a homogeneous population of receptors in five separate, highly-reproducible, experiments. In contrast, the replicate data sets obtained from the interaction in the isolated, lumen-perfused mouse stomach and guinea-pig gastric muscle assays, over the same period, were not consistent with the presence of a single receptor population. The guinea-pig gastric muscle data were relatively reproducible between experiments but some individual Schild plot slopes and the slope estimated from a global analysis of all the data were significantly less than unity (slope = 0.80 +/- 0.07, pA2 = 8.56 +/- 0.05 from the global analysis). The data obtained in the mouse stomach were significantly more variable than that obtained in the same assay, during the same period, from the interaction between histamine and the H2-receptor antagonist, famotidine. The individual Schild plot slopes ranged from being very flat (0.20) to being not significantly different from unity (1.23) and the pA2 values ranged from 7.68 to 8.70. 3. Overall, the data could be accounted for by assuming the variable expression of two receptor subtypes across the assays. The rat stomach appeared to express a single receptor characterized by a low affinity constant for L-365,260 (pKB approximately 7.5). The guinea-pig gastric muscle and mouse stomach data could be explained by the presence of this receptor and a second one characterized by a high affinity constant for L-365,260 (pKB approximately 8.6). The activity of the two proposed receptor subtypes was consistent between experiments in the guinea-pig and the high affinity receptor appeared to be predominant. In contrast, the mouse stomach data could only be simulated by assuming that the proportion and absolute number of each subtype varied significantly between the replicate experiments. 4. The L-365,260 affinity estimates at the inferred receptor subtypes were indistinguishable from those obtained in a corresponding analysis of the behaviour of L-365,260 in CCKB/gastrin receptor radioligand binding experiments in guinea-pig gastric gland and mouse and rat cerebral cortex preparations.


Asunto(s)
Benzodiazepinonas/farmacología , Mucosa Gástrica/metabolismo , Compuestos de Fenilurea , Receptores de Colecistoquinina/antagonistas & inhibidores , Animales , Unión Competitiva/efectos de los fármacos , Famotidina/farmacología , Cobayas , Histamina/farmacología , Antagonistas de los Receptores H2 de la Histamina/farmacología , Técnicas In Vitro , Ratones , Músculo Liso/efectos de los fármacos , Músculo Liso/metabolismo , Pentagastrina/farmacocinética , Ratas , Ratas Wistar , Receptores de Colecistoquinina/metabolismo , Especificidad de la Especie , Estómago/efectos de los fármacos
10.
J Evol Biol ; 14(1): 75-82, 2001 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-29280581

RESUMEN

To examine how the duration of laboratory domestication may affect Drosophila stocks used in studies of thermotolerance, we measured expression of the inducible heat-shock protein Hsp70 and survival after heat shock in D. melanogaster strains recently collected from nature and maintained in laboratory culture for up to 50 or more generations. After an initial increase in both Hsp70 expression and thermotolerance immediately after transfer to laboratory medium, both traits remained fairly constant over time and variation among strains persisted through laboratory domestication. Furthermore, variation in heat tolerance and Hsp70 expression did not correlate with the length of time populations evolved in the laboratory. Therefore, while environmental variation likely contributed most to early shifts in strain tolerance and Hsp70 expression, other population parameters, for example genetic drift, inbreeding, and selection likely affected these traits little. As long as populations are maintained with large numbers of individuals, the culture of insects in the laboratory may have little effect on the tolerance of different strains to thermal stress.

11.
J Clin Pathol ; 45(4): 361-3, 1992 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-1577980

RESUMEN

A middle aged man developed very high fever, status epilepticus, and terminal acute renal failure with myoglobinuria after surgery. A post mortem examination showed widespread muscle necrosis with hypercontraction bands. Muscle enzyme studies and electron microscopic examination disclosed central core disease, a condition closely related to malignant hyperpyrexia. This condition is a genetically inherited disorder which can be triggered by certain volatile anaesthetic agents or Suxamethonium. In this patient the condition may have been triggered by either the Isoflurane or the postoperative status epilepticus.


Asunto(s)
Hipertermia Maligna/patología , Enfermedades Musculares/patología , Complicaciones Posoperatorias/patología , Humanos , Isoflurano/efectos adversos , Masculino , Hipertermia Maligna/etiología , Persona de Mediana Edad , Necrosis , Estado Epiléptico/complicaciones
12.
Naunyn Schmiedebergs Arch Pharmacol ; 345(3): 327-32, 1992 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-1352382

RESUMEN

The present study investigated the effects of SK&F 104078 (6-chloro-9-[(3-methyl-2-butenyl)oxy]-3-methyl-1H,2,3,4,- tetrahydro-3-benzazapine) at pre- and post-junctional alpha 2-adrenoceptors in the human isolated saphenous vein. Noradrenaline (0.001-100 mumol/l) produced concentration-dependent contractions of the human saphenous vein which were competitively antagonised by the alpha 1-adrenoceptor antagonist prazosin (0.01-1.0 mumol/l) and the alpha 2-adrenoceptor antagonist, rauwolscine (0.01-1.0 mumol/l), indicating the presence of both post-junctional alpha 1- and alpha 2-adrenoceptors in this preparation. The selective alpha 2-adrenoceptor agonist, UK-14,304 (0.01-100 mumol/l) also produced concentration-dependent contractions of the human saphenous vein which were antagonised by both rauwolscine (0.1 mumol/l) and prazosin (0.1 mumol/l). In the presence of angiotensin II (0.05 mumol/l), which itself produced a transient contraction, rauwolscine (0.1 mumol/l) produced a rightward shift of the UK-14,304 concentration-response curve while prazosin (0.1 mumol/l) had no effect. SK&F 104078 (10.0 mumol/l) under these conditions also produced a rightward shift of the concentration-response curve to UK-14,304, but was at least 100-fold less potent than rauwolscine. At pre-junctional alpha 2-adrenoceptors, exogenous noradrenaline (0.01 and 0.1 mumol/l) induced a concentration-dependent inhibition of stimulation-evoked [7-3H]-noradrenaline release from the human saphenous vein in vitro, which was antagonised by rauwolscine (0.1 mumol/l) and tolazoline (10.0 mumol/l) but not by SK&F 104078 (10.0 mumol/l).(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Antagonistas Adrenérgicos alfa/farmacología , Benzazepinas/farmacología , Vena Safena/efectos de los fármacos , Agonistas alfa-Adrenérgicos/farmacología , Adulto , Anciano , Tartrato de Brimonidina , Humanos , Técnicas In Vitro , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/ultraestructura , Unión Neuromuscular/efectos de los fármacos , Unión Neuromuscular/ultraestructura , Norepinefrina/farmacología , Quinoxalinas/farmacología , Vena Safena/ultraestructura
13.
Oecologia ; 121(3): 323-329, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28308320

RESUMEN

We demonstrate that natural heat stress on wild larval Drosophila melanogaster results in severe developmental defects in >10% of eclosing adults, and that increased copy number of the gene encoding the major inducible heat shock protein of D. melanogaster, Hsp70, is sufficient to reduce the incidence of such abnormalities. Specifically, non-adult D. melanogaster inhabiting necrotic fruit experienced severe, often lethal heat stress in natural settings. Adult flies eclosing from wild larvae that had survived natural heat stress exhibited severe developmental anomalies of wing and abdominal morphology, which should dramatically affect fitness. The frequency of developmental abnormalities varied along two independent natural thermal gradients, exceeding 10% in adults eclosing from larvae developing in warm, sunlit fruit. When exposed to natural heat stress, D. melanogaster larvae with the wild-type number of hsp70 genes (n=10) developed abnormal wings significantly more frequently than a transgenic sister strain with 22 copies of the hsp70 gene.

14.
Oecologia ; 123(4): 460-465, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28308753

RESUMEN

The expression of two temperature-sensitive reporter genes, hsp70 and an hsp70-LacZ fusion, in free-ranging adult Drosophila melanogaster indicates that natural thermal stress experienced by such small and mobile insects may be either infrequent or not severe. Levels of the heat-shock protein Hsp70, the major inducible Hsp of Drosophila, were similar in most wild Droso- phila captured after warm days to levels previously reported for unstressed flies in the laboratory. In a transgenic strain transformed with an hsp70-LacZ fusion (i.e., the structural gene encoding bacterial ß-galactosidase under control of a heat shock promoter), exposure to temperatures ≥32°C in the laboratory typically resulted in ß-galactosidase activities exceeding 140 mOD450 h-1µg-1 soluble protein. Flies caged in sun frequently had ß-galactosidase activities in excess of this level, whereas flies caged in shade and flies released and recaptured on cool days did not. Most flies (>80%) released on warm, sunny days had low ß-galactosidase activities upon recapture. Although the balance of recaptured flies had elevated ß-galactosidase activities on these days, their ß-galactosidase activities were <50% of levels for flies caged in direct sunlight or exposed to laboratory heat shock. These data suggest that even on warm days most flies may avoid thermal stress, presumably through microhabitat selection, but that a minority of adult D. melanogaster undergo mild thermal stress in nature. Both temperature-sensitive reporter genes, however, are limited in their ability to infer thermal stress and demonstrate its absence.

15.
Magn Reson Imaging ; 12(2): 355-9, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-8170338

RESUMEN

The use of solid state NMR imaging in reservoir core applications has long been proposed. This paper describes the use of a simple, robust technique in the first such application. One- and two-dimensional images of the irreducible brine in a sandstone and carbonate reservoir core are demonstrated. The applicability of solid state NMR imaging to pore surface relaxation estimation is discussed.


Asunto(s)
Imagen por Resonancia Magnética , Carbonatos , Espectroscopía de Resonancia Magnética , Petróleo , Sales (Química)
17.
Insect Mol Biol ; 16(4): 435-43, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17506850

RESUMEN

We exposed adult male Drosophila melanogaster to cold, desiccation or starvation, and examined expression of several genes during exposure and recovery. Frost was expressed during recovery from cold, and was up-regulated during desiccation. Desiccation and starvation (but not cold) elicited increased expression of the senescence-related gene smp-30. Desat2 decreased during recovery from desiccation, but not in response to starvation or cold. Hsp70 expression increased after 1 h of recovery from cold exposure, but was unchanged in response to desiccation or starvation stress, and Hsp23 levels did not respond to any of the stressors. We conclude that D. melanogaster's responses to cold and desiccation are quite different and that care must be taken to separate exposure and recovery when studying responses to environmental stress.


Asunto(s)
Adaptación Fisiológica/fisiología , Frío , Drosophila melanogaster/genética , Drosophila melanogaster/fisiología , Adaptación Fisiológica/genética , Animales , Deshidratación/genética , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Regulación de la Expresión Génica , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Transcripción Genética , Regulación hacia Arriba
18.
Science ; 313(5785): 351-4, 2006 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-16857940

RESUMEN

Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage and location, pollinator declines were most frequent in habitat and flower specialists, in univoltine species, and/or in nonmigrants. In conjunction with this evidence, outcrossing plant species that are reliant on the declining pollinators have themselves declined relative to other plant species. Taken together, these findings strongly suggest a causal connection between local extinctions of functionally linked plant and pollinator species.


Asunto(s)
Abejas , Biodiversidad , Dípteros , Ecosistema , Plantas , Polen , Migración Animal , Animales , Ambiente , Flores , Países Bajos , Dinámica Poblacional , Reino Unido
19.
J Exp Biol ; 208(Pt 18): 3543-51, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16155226

RESUMEN

Hemoglobin (Hb) is a highly conserved protein that provides a vital link between environmental oxygen and its use and/or storage within an organism. While ubiquitous among vertebrates, Hb occurs frequently in invertebrate phyla as well. Many arthropod species use the copper-binding pigment hemocyanin, but unique in this phylum are the branchiopod crustaceans, which express Hb. Branchiopod Hb concentration and structure are exquisitely sensitive to environmental oxygen availability. Hemoglobin concentration and oxygen-binding affinity increase with decreasing oxygen tension in Daphnia, Artemia and Triops. The change in binding affinity is attributed to differential Hb subunit expression in Daphnia and Artemia but remains unclear for Triops. This is the first study to demonstrate developmental plasticity of Hb subunit expression in a notostracan, Triops longicaudatus, reared under conditions of varying oxygen availability. In response to variable oxygen environments, T. longicaudatus differentially express four primary Hb subunits ranging between 30 and 34 kDa, with normoxic-reared animals expressing primarily the heavier subunits, and hypoxic-reared animals expressing increased proportions of the lower molecular mass subunits. Moreover, differential Hb subunit expression is induced upon transfer of normoxic-reared adults to a hypoxic environment, such that the distribution of Hb subunits in the transferred adults becomes similar to that of hypoxic-reared animals. Two-dimensional gel electrophoresis and follow-up analyses revealed several isoforms of Hb subunits that may represent differential gene expression and/or post-translational modification. Unlike Daphnia and Artemia, the Hb hypoxic response in Triops is not reversible in that there was no significant decrease in Hb concentration or change in Hb subunit expression pattern when hypoxic-reared adults were transferred to a normoxic environment.


Asunto(s)
Crustáceos/fisiología , Regulación de la Expresión Génica/fisiología , Hemoglobinas/metabolismo , Hipoxia/sangre , Oxígeno/metabolismo , Secuencia de Aminoácidos , Análisis de Varianza , Animales , Crustáceos/metabolismo , Electroforesis en Gel Bidimensional , Fluorescencia , Hemoglobinas/genética , Hipoxia/metabolismo , Datos de Secuencia Molecular , Nevada , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Análisis de Secuencia de Proteína
20.
J Am Optom Assoc ; 63(10): 723-32, 1992 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-1430747

RESUMEN

Following stroke or other causes of brain damage, patients may demonstrate visual disorders of higher cortical function. These defects involve visual attention, oculomotor skills, visuospatial orientation and object recognition. It is important for optometrists to understand these conditions and consider their presence in individuals with persistent visual complaints despite a normal exam, or in patients who fail to respond to magnification in low vision rehabilitation. The diagnosis and management of these higher order visual disturbances are discussed.


Asunto(s)
Trastornos de la Visión/diagnóstico , Agnosia/diagnóstico , Agnosia/terapia , Agrafia/diagnóstico , Agrafia/terapia , Apraxias/diagnóstico , Apraxias/terapia , Encefalopatías/complicaciones , Humanos , Enfermedades del Nervio Óptico/diagnóstico , Trastornos de la Visión/etiología , Corteza Visual
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