Differential expression of microRNAs in mouse pain models

Background: MicroRNAs (miRNAs) are short non-coding RNAs that inhibit translation of target genes by binding to their mRNAs. The expression of numerous brain-specific miRNAs with a high degree of temporal and spatial specificity suggests that miRNAs play an important role in gene regulation in health and disease. Here we investigate the time course gene expression profile of miR-1, -16, and -206 in mouse dorsal root ganglion (DRG), and spinal cord dorsal horn under inflammatory and neuropathic pain conditions as well as following acute noxious stimulation. Results: Quantitative real-time polymerase chain reaction analyses showed that the mature form of miR-1, -16 and -206, is expressed in DRG and the dorsal horn of the spinal cord. Moreover, CFA-induced inflammation significantly reduced miRs-1 and -16 expression in DRG whereas miR-206 was downregulated in a time dependent manner. Conversely, in the spinal dorsal horn all three miRNAs monitored were upregulated. After sciatic nerve partial ligation, miR-1 and -206 were downregulated in DRG with no change in the spinal dorsal horn. On the other hand, axotomy increases the relative expression of miR-1, -16, and 206 in a time-dependent fashion while in the dorsal horn there was a significant downregulation of miR-1. Acute noxious stimulation with capsaicin also increased the expression of miR-1 and -16 in DRG cells but, on the other hand, in the spinal dorsal horn only a high dose of capsaicin was able to downregulate miR-206 expression. Conclusions: Our results indicate that miRNAs may participate in the regulatory mechanisms of genes associated with the pathophysiology of chronic pain as well as the nociceptive processing following acute noxious stimulation. We found substantial evidence that miRNAs are differentially regulated in DRG and the dorsal horn of the spinal cord under different pain states. Therefore, miRNA expression in the nociceptive system shows not only temporal and spatial specificity but is also stimulus-dependent.

Resistance Training with Vascular Occlusion in Inclusion Body Myositis: A Case Study

GUALANO, B., M. NEVES JR, F. R. LIMA, A. L. PINTO, G. LAURENTINO, C. BORGES, L. BAPTISTA, G. G. ARTIOLI, M. S. AOKI, A. MORISCOT, A. H. LANCHA JR, E. BONFA, and C. UGRINOWITSCH. Resistance Training with Vascular Occlusion in Inclusion Body Myositis: A Case Study. Med Sci. Spot-is Exerc., Vol. 42, No. 2, pp. 250-254, 2010. Inclusion body myositis (IBM) is a rare idiopathic inflammatory myopathy that produces remarkable muscle weakness. Resistance training with vascular occlusion has been shown to improve muscle strength and cross-sectional area in other muscle wasting conditions. Purpose: We evaluated the efficacy of a moderate-intensity resistance training program combined with vascular occlusion by examining functional capacity, muscle morphology, and changes in the expression of genes related to muscle protein synthesis and proteolysis in a patient with IBM. Methods: A 65-yr-old man with IBM resistant to all proposed treatments underwent resistance training with vascular occlusion for 12 wk. Leg press one-repetition maximum; thigh cross-sectional area; balance, mobility, and muscle function; quality of life; and blood markers of inflammation and muscle damage were assessed at baseline and after the 12-wk program. The messenger RNA (mRNA) expression levels of mechanogrowth factor, mammalian target of rapamycin, atrogin-1, and muscle RING finger-1 were also quantified. Results: After the 12-wk training program, the patient`s leg press one-repetition maximum, balance and mobility function, and thigh cross-sectional area increased 15.9%, 60%, and 4.7%, respectively. All Short Form-36 Health Survey Questionnaire subscales demonstrated improvements as well, varying from 18% to 600%. mRNA expression of mechanogrowth factor increased 3.97-fold, whereas that of atrogin-1 decreased 0.62-fold. Muscle RING finger-1 and mammalian target of rapamycin mRNA levels were only slightly altered, 1.18- and 1.28-fold, respectively. Importantly, the exercise did not induce disease flare. Conclusions: We describe a novel, and likely the first, nonpharmacological therapeutic tool that might be able to counteract the muscle atrophy and the declining strength that usually occur in IBM.

MACRONUTRIENTS UPTAKE BY POTATO (Solanum tuberosum L.) IN SEED-TUBER PRODUCTION

In greenhouse potato cultivation, mineral nutrition is one of the main factors contributing to high yields and better product quality. Knowledge about the amount of nutrients accumulated in the plants at each growing phase provides important information that helps the establishment of a more balanced fertilizer application. The objective of this research was to determine the time course of macronutrients uptake and accumulation in potato plants for seed-tuber production, grown in nutrient solution. The experiment was carried out in a greenhouse, using in vitro material from the pre-basic category of the `Atlantic` variety. The plants were collected weekly from 14 days after transplanting (DAT) until 70 DAT The experimental design was a completely randomized block with 9 treatments to sampling times and four replicates. The highest nutrient requirement in the plant shoot occurred at the periods between 28 and 56 DAT while in the tubers it was after 49 DAT The maximum accumulation sequence of macronutrients was K > N > S > Ca > P > Mg.

Out of the Andes: patterns of diversification in clearwing butterflies

Global biodiversity peaks in the tropical forests of the Andes, a striking geological feature that has likely been instrumental in generating biodiversity by providing opportunities for both vicariant and ecological speciation. However, the role of these mountains in the diversification of insects, which dominate biodiversity, has been poorly explored using phylogenetic methods. Here we study the role of the Andes in the evolution of a diverse Neotropical insect group, the clearwing butterflies. We used dated species-level phylogenies to investigate the time course of speciation and to infer ancestral elevation ranges for two diverse genera. We show that both genera likely originated at middle elevations in the Andes in the Middle Miocene, contrasting with most published results in vertebrates that point to a lowland origin. Although we detected a signature of vicariance caused by the uplift of the Andes at the Miocene-Pliocene boundary, most sister species were parapatric without any obvious vicariant barrier. Combined with an overall decelerating speciation rate, these results suggest an important role for ecological speciation and adaptive radiation, rather than simple vicariance.

Secretory phospholipases A(2) isolated from Bothrops asper and from Crotalus durissus terrificus snake venoms induce distinct mechanisms for biosynthesis of prostaglandins E-2 and D-2 and expression of cyclooxygenases

The effects of myotoxin III (MT-III), a phospholipase A(2) (sPLA(2)) from Bothrops asper snake venom, and crotoxin B (CB), a neurotoxic and myotoxic sPLA2 from the venom of Crotalus durissus terrificus, on cyclooxygenases (COXs) expression and biosynthesis of prostaglandins (PGs) were evaluated, together with the mechanisms involved in these effects. Upon intraperitoneal injection in mice, both sPLA(2)s promoted the synthesis of PGD(2) and PGE(2), with a different time-course. MT-III, but not CB, induced COX-2 expression by peritoneal leukocytes without modification on COX-1 constitutive expression, whereas CB increased the constitutive activity of COX-1. MT-III increased the enzymatic activity of COX-1 and COX-2. Similar effects were observed when these sPLA(2)s were incubated with isolated macrophages, evidencing a direct effect on these inflammatory cells. Moreover, both toxins elicited the release of arachidonic acid from macrophages in vitro. inhibition of cPLA(2) by AACOCF(3), but not of iPLA(2) by PACOCF(3) or BEL, significantly reduced PGD2, PGE2 and arachidonic acid (AA) release promoted by MT-III. These inhibitors did not affect MT-III-induced COX-2 expression. In contrast, cPLA2 inhibition did not modify the effects of CB, whereas iPLA2 inhibition reduced PGD2 and AA production induced by CB. These findings imply that distinct regulatory mechanisms leading to PGs` synthesis are triggered by these snake venom sPLA(2)s. Such differences are likely to explain the dissimilar patterns of inflammatory reaction elicited by these sPLA(2)s in vivo. (C) 2008 Elsevier Ltd. All rights reserved.

Morphosyntactic and syntactic priming: an investigation of underlying processing mechanisms and the effects of Parkinson’s disease

There is now considerable evidence to suggest that non-demented people with Parkinson's disease (PD) experience difficulties using the morphosyntactic aspects of language. It remains unclear, however, at precisely which point in the processing of morphosyntax, these difficulties emerge. The major objective of the present study was to examine the impact of PD on the processes involved in accessing morphosyntactic information in the lexicon. Nineteen people with PD and 19 matched control subjects participated in the study which employed on-line word recognition tasks to examine morphosyntactic priming for local grammatical dependencies that occur both within (e.g. is going) and across (e.g. she gives) phrasal boundaries (Experiments 1 and 2, respectively). The control group evidenced robust morphosyntactic priming effects that were consistent with the involvement of both pre- (Experiment 1) and post-lexical (Experiment 2) processing routines. Whilst the participants with PD also recorded priming for dependencies within phrasal boundaries (Experiment 1), priming effects were observed over an abnormally brief time course. Further, in contrast to the controls, the PD group failed to record morphosyntactic priming for constructions that crossed phrasal boundaries (Experiment 2). The results demonstrate that attentionally mediated mechanisms operating at both the pre- and post-lexical stages of processing are able to contribute to morphosyntactic priming effects. In addition, the findings support the notion that, whilst people with PD are able to access morphosyntactic information in a normal manner, the time frame in which this information remains available for processing is altered. Deficits may also be experienced at the post-lexical integrational stage of processing.

Improving wheat simulation capabilities in Australia from a cropping systems perspective - II. Testing simulation capabilities of wheat growth

To simulate cropping systems, crop models must not only give reliable predictions of yield across a wide range of environmental conditions, they must also quantify water and nutrient use well, so that the status of the soil at maturity is a good representation of the starting conditions for the next cropping sequence. To assess the suitability for this task a range of crop models, currently used in Australia, were tested. The models differed in their design objectives, complexity and structure and were (i) tested on diverse, independent data sets from a wide range of environments and (ii) model components were further evaluated with one detailed data set from a semi-arid environment. All models were coded into the cropping systems shell APSIM, which provides a common soil water and nitrogen balance. Crop development was input, thus differences between simulations were caused entirely by difference in simulating crop growth. Under nitrogen non-limiting conditions between 73 and 85% of the observed kernel yield variation across environments was explained by the models. This ranged from 51 to 77% under varying nitrogen supply. Water and nitrogen effects on leaf area index were predicted poorly by all models resulting in erroneous predictions of dry matter accumulation and water use. When measured light interception was used as input, most models improved in their prediction of dry matter and yield. This test highlighted a range of compensating errors in all modelling approaches. Time course and final amount of water extraction was simulated well by two models, while others left up to 25% of potentially available soil water in the profile. Kernel nitrogen percentage was predicted poorly by all models due to its sensitivity to small dry matter changes. Yield and dry matter could be estimated adequately for a range of environmental conditions using the general concepts of radiation use efficiency and transpiration efficiency. However, leaf area and kernel nitrogen dynamics need to be improved to achieve better estimates of water and nitrogen use if such models are to be use to evaluate cropping systems. (C) 1998 Elsevier Science B.V.

An exploration of varieties of visual attention: ERP findings

A set of five tasks was designed to examine dynamic aspects of visual attention: selective attention to color, selective attention to pattern, dividing and switching attention between color and pattern, and selective attention to pattern with changing target. These varieties of visual attention were examined using the same set of stimuli under different instruction sets; thus differences between tasks cannot be attributed to differences in the perceptual features of the stimuli. ERP data are presented for each of these tasks. A within-task analysis of different stimulus types varying in similarity to the attended target feature revealed that an early frontal selection positivity (FSP) was evident in selective attention tasks, regardless of whether color was the attended feature. The scalp distribution of a later posterior selection negativity (SN) was affected by whether the attended feature was color or pattern. The SN was largely unaffected by dividing attention across color and pattern. A large widespread positivity was evident in most conditions, consisting of at least three subcomponents which were differentially affected by the attention conditions. These findings are discussed in relation to prior research and the time course of visual attention processes in the brain. (C) 1999 Elsevier Science B.V. All rights reserved.

Effects of beta-escin and saponin on the transverse-tubular system and sarcoplasmic reticulum membranes of rat and toad skeletal muscle

Mechanically skinned skeletal muscle fibres from rat and toad were exposed to the permeabilizing agents beta-escin and saponin. The effects of these agents on the sealed transverse tubular system (t-system) and sarcoplasmic reticulum (SR) were examined by looking at changes in the magnitude of the force responses to t-system depolarization, the time course of the fluorescence of fura-2 trapped in the sealed t-system, and changes in the magnitude of caffeine-induced contractures following SR loading with Ca2+ under defined conditions. In the presence of 2 mu g ml(-1) beta-escin and saponin, the response to t-system depolarization was not completely abolished, decreasing to a plateau, and a large proportion of fura-2 remained in the sealed t-system. At 10 mu g ml(-1), both agents abolished the ability of both rat and toad preparations to respond to t-system depolarization after 3 min of exposure, but a significant amount of fura-2 remained in sealed t-tubules even after exposure to 100 mu g ml(-1) beta-escin and saponin for 10 min. beta-Escin took longer than saponin to reduce the t-system depolarizations and fura-2 content of the sealed t-system to a similar level. The ability of the SR to load Ca2+ was reduced to a lower level after treatment with beta-escin than saponin. This direct effect on the SR occurred at much lower concentrations for rat (2 mu g ml(-1) beta-escin and 10 mu g ml(-1) saponin) than toad (10 mu g ml(-1) beta-escin and 150 mu g ml(-1) saponin). The reverse order in sensitivities to beta-escin and saponin of t-system and SR membranes indicates that the mechanisms of action of beta-escin and saponin are different in the two types of membrane. In conclusion, this study shows that: (1) beta-escin has a milder action on the surface membrane than saponin; (2) beta-escin is a more potent modifier of SR function; (3) simple permeabilization of membranes is not sufficient to explain the effects of beta-escin and saponin on muscle membranes; and (4) the t-system network within muscle fibres is not a homogeneous compartment.

Cell death and immunohistochemistry of p53, c-Fos and c-Jun after spermine infection into the rat striatum

Administration of polyamines into the central nervous system results in tissue damage, possibly through the excitotoxic actions of the NMDA receptor. Direct injection of 100 nmol of spermine into the rat striatum produced a lesion equivalent to approximately 50% of the striatum. Analysis of the DNA in this region revealed the distinct ladder-like pattern of degradation often associated with apoptosis. This DNA fragmentation was confirmed in vivo using terminal deoxynucleotidyl-transferase-mediated biotinylated deoxyuridine triphosphate nick end labelling (TUNEL). The morphology of the TUNEL-positive cells showed marked differences at the needle tract when compared with cells in damaged areas away from the needle tract, suggesting a differential mechanism of cell death in these two regions. The patterns of p53, c-Fos and c-Jun protein expression were determined using immunohistochemistry. The number of p53-immunoreactive cells increased up to 14 h and returned to basal levels by 24 h. c-Fos protein expression transiently increased, peaking at 8 h after injection, c-Jun exhibited a protracted pattern of expression, remaining elevated up to 24 h. p53 protein expression was colocalised with TUNEL staining in areas away from the needle tract, but not in cells at the needle tract, suggesting once again a differential mechanism of cell death. At 14 h, c-Fos and c-Jun were not colocalised with TUNEL staining, suggesting that they are either not involved with the cell death process or that the time course of protein expression and the onset of DNA fragmentation do not overlap. This work represents the first characterisation of processes associated with cell death induced by spermine in vivo.

Kinetics of propranolol uptake in muscle, skin, and fat of the isolated perfused rat hindlimb

The tissue distribution kinetics of a highly bound solute, propranolol, was investigated in a heterogeneous organ, the isolated perfused limb, using the impulse-response technique and destructive sampling. The propranolol concentration in muscle, skin, and fat as well as in outflow perfusate was measured up to 30 min after injection. The resulting data were analysed assuming (1) vascular, muscle, skin and fat compartments as well mixed (compartmental model) and (2) using a distributed-in-space model which accounts for the noninstantaneous intravascular mixing and tissue distribution processes but consists only of a vascular and extravascular phase (two-phase model). The compartmental model adequately described propranolol concentration-time data in the three tissue compartments and the outflow concentration-time curve (except of the early mixing phase). In contrast, the two-phase model better described the outflow concentration-time curve but is limited in accounting only for the distribution kinetics in the dominant tissue, the muscle. The two-phase model well described the time course of propranolol concentration in muscle tissue, with parameter estimates similar to those obtained with the compartmental model. The results suggest, first that the uptake kinetics of propranolol into skin and fat cannot be analysed on the basis of outflow data alone and, second that the assumption of well-mixed compartments is a valid approximation from a practical point of view las, e.g., in physiological based pharmacokinetic modelling). The steady-state distribution volumes of skin and fat were only 16 and 4%, respectively, of that of muscle tissue (16.7 ml), with higher partition coefficient in fat (6.36) than in skin (2.64) and muscle (2.79. (C) 2000 Elsevier Science B.V. All rights reserved.

Why do non-color words interfere with color naming?

In the non-color-word Stroop task, university students' response latencies were longer for low-frequency than for higher frequency target words. Visual identity primes facilitated color naming in groups reading the prime silently or processing it semantically (Experiment 1) but did not when participants generated a rhyme of the prime (Experiment 3). With auditory identity primes, generating an associate or a rhyme of the prime produced interference (Experiments 2 and 3). Color-naming latencies were longer for nonwords than for words (Experiment 4). There was a small long-term repetition benefit in color naming for low-frequency words that had been presented in the lexical decision task (Experiment 5). Facilitation of word recognition speeds color naming except when phonological activation of the base word increases response competition.

Properties of the vertebrate skeletal muscle tubular system as a sealed compartment

Confocal imaging of impermeant fluorescent dyes trapped in the tubular (t-) system of skeletal muscle fibres of rat and cane toad was used to examine changes in the morphology of the t-system upon mechanical skinning, the time course of dye loss from the sealed t-systern in mechanically skinned fibres and the influence of rapid application and removal of glycerol on the morphology of the sealed t-system. In contrast to intact fibres, which have a t-systern open to the outside, the sealed t-systern of toad mechanically skinned fibres consistently displayed local swellings (vesicles). The occurrence of vesicles in the sealed t-system of rat-skinned fibres was infrequent. Application and removal of 200-400 mM glycerol to the sealed t-system did not produce any obvious changes in its morphology. The dyes fluo-3, fura-2 and Oregon green 488 were lost from the sealed t-system of toad fibres at different rates suggesting that the mechanism of organic anion transport across the tubular wall was not by indiscriminate bulk transport. The rate of fluo-3 and fura-2 loss from the sealed t-system of rat fibres was greater in rat than in toad fibres and could be explained by differences in surface area: volume ratio of the t-system in the two fibre types. Based on the results presented here and on other results from this laboratory, an explanation is given for the formation of numerous vesicles in toad-skinned fibres and lack of vesicle formation in rat-skinned fibres. This explanation can also help with better understanding the mechanism responsible for vacuole formation in intact fibres. (C) 2002 Elsevier Science Ltd. All rights reserved.

Can I have your attention please: Repressors and enhanced P3 to emotional stimuli

In four experiments ERPs to emotional (negative and positive) and neutral stimuli were examined as a function of participants’ trait anxiety and repressivedefensiveness. The experiments investigated the time course of attentional bias in the processing of such stimuli. Pictures of angry, happy, and neutral faces were used in two of the experiments and pictures ofmutilated, happy, and neutral faces were used in the others. ERP’s to emotional and neutral stimuli were recorded from parietal, temporal, and frontal sites. Analysis of the P3 component indicated that the peak magnitude of the P3 at the parietal and temporal sites reflected an interactive function of trait anxiety and defensiveness. Repressors (low reported anxiety, high defensiveness) showed a consistent pattern of greater P3 magnitude at the parietal and temporal sites for emotional faces (angry, happy, and mutilated) than did high-anxious and low-anxious participants. Participants did not differ in P3 magnitude when ERPs to neutral stimuli were investigated (e.g., a fixation cross). The findings indicate that Repressors dedicate greater processing resources to emotional material, as compared to neutral material, than either the high-anxious or low-anxious individuals. Results of the four experiments are discussed within the theoretical framework of Derakshan and Eysenck (1998). The importance of understanding the role of differences in information processing, in the experience and avoidance of emotional information, as a function of trait anxiety and defensiveness is emphasized.