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Selected AbstractsSurface EMG of jaw-elevator muscles and chewing pattern in complete denture wearersJOURNAL OF ORAL REHABILITATION, Issue 12 2005M. G. PIANCINO summary, The aim of this study was to investigate the adaptation process of masticatory patterns to a new complete denture in edentulous subjects. For this purpose, muscle activity and kinematic parameters of the chewing pattern were simultaneously assessed in seven patients with complete maxillary and mandibular denture. The patients were analysed (i) with the old denture, (ii) with the new denture at the delivery, (iii) after 1 month and (iv) after 3 months from the delivery of the new denture. Surface electromyographic (EMG) signals were recorded from the masseter and temporalis anterior muscles of both sides and jaw movements were tracked measuring the motion of a tiny magnet attached at the lower inter-incisor point. The subjects were asked to chew a bolus on the right and left side. At the delivery of the new denture, peak EMG amplitude of the masseter of the side of the bolus was lower than with the old denture and the masseters of the two sides showed the same intensity of EMG activity, contrary to the case with the old denture. EMG amplitude and asymmetry of the two masseter activities returned as with the old denture in 3 months. The EMG activity in the temporalis anterior was larger with the old denture than in the other conditions. The chewing cycle width and lateral excursion decreased at the delivery of the new denture and recovered after 3 months. [source] DICHOTOMY OF CORTICAL PAIN PROCESSINGPAIN MEDICINE, Issue 2 2002Article first published online: 4 JUL 200 Jahangir Maleki, Rollin M. Gallagher, Pain Medicine and Rehabilitation Center, MCP/Hahnemann School of Medicine Introduction: Functional MRI and PET studies of cortical pain processing indicate segregated pain pathways above the thalamus. Although experimental pain may result in multiple areas of altered cortical activity, it is postulated that thalamic pain fibers known as the lateral system, projecting to sensory cortex, serve to localize pain, whereas medial pathways projecting to limbic cortex, process affective aspects of pain. Case Study: A 27 y/o female, with left upper extremity pain and severe allodynia from Complex Regional Pain Syndrome, Type I (CRPS I / RSD), after receiving intra-pleural bupivacaine blocks developed an ipsilateral focal-onset secondary generalized tonic clonic seizure. This was followed by one hour of post-ictal confusion. Simultaneously she developed a dense left-sided motor and sensory deficit (Todd's palsy) with a motor deficit resolving in one day whereas a sensory deficit lasted 2 days. Throughout the duration of the sensory deficit she denied any left arm pain, although she continued to report the same intensity of pain, but now localized to her epigastric region. Interestingly, despite the lack of sensory perception on the left side, palpation of her left arm resulted in increased epigastric pain and suffering. Discussion: This case indicates a bifurcation of the pain pathway between the thalamus and cortex. Due to focal seizure activity, the sensory cortex (i.e. lateral system) was transiently rendered dysfunctional, during which time the continued presence of pain and allodynia without appropriate localization likely resulted from pain conduction, from the thalamus to functional limbic structures such as Cingulum (i.e. via the medial fibre system). Conclusion: This case report strongly supports the hypothesis of medial and lateral pain conducting fibers branching at the level of thalamus with medial sub-serving the emotional aspects of pain by projection to limbic cortex, whereas lateral fibres project to sensory cortex, primarily serving a localizing function. [source] Root growth dynamics of Nicotiana attenuata seedlings are affected by simulated herbivore attackPLANT CELL & ENVIRONMENT, Issue 10 2007GRÉGOIRE M. HUMMEL ABSTRACT Many studies demonstrate resource-based trade-offs between growth and defence on a large timescale. Yet, the short-term dynamics of this growth reaction are still completely unclear, making it difficult to explain growth-defence trade-offs mechanistically. In this study, image-based non-destructive methods were used to quantify root growth reactions happening within hours following simulated herbivore attack. The induction of wound reactions in Nicotiana attenuata in the seedling stage led to transiently decreased root growth rates. Application of the oral secretion of the specialist herbivore Manduca sexta to the leaves led to a transient decrease in root growth that was more pronounced than if a mere mechanical wounding was imposed. Root growth reduction was more pronounced than leaf growth reduction. When fatty acid,amino acid conjugates (FACs) were applied to wounds, root growth reduction occurred in the same intensity as when oral secretion was applied. Timing of the transient growth reduction coincided with endogenous bursts of jasmonate (JA) and ethylene emissions reported in literature. Simulation of a wound response by applying methyl jasmonate (MeJA) led to more prolonged negative effects on root growth. Increased nicotine concentrations, trichome lengths and densities were observed within 72 h in seedlings that were treated with MeJA or that were mechanically wounded. Overall, these reactions indicate that even in a very early developmental stage, the diversion of plant metabolism from primary (growth-sustaining) to secondary (defence-related) metabolism can cause profound alterations of plant growth performance. [source] Interhemispheric interaction between human dorsal premotor and contralateral primary motor cortexTHE JOURNAL OF PHYSIOLOGY, Issue 1 2004Hitoshi Mochizuki We used transcranial magnetic stimulation (TMS) in a paired pulse protocol to investigate interhemispheric interactions between the right dorsal premotor (dPM) and left primary motor cortex (M1) using interstimulus intervals of 4, 6, 8, 10, 12, 16 and 20 ms in ten healthy subjects. A conditioning stimulus over right dPM at an intensity of either 90 or 110% resting motor threshold (RMT) suppressed motor-evoked potentials (MEPs) evoked in the first dorsal interosseous (FDI) muscle by stimulation of left M1. Maximum effects occurred for interstimulus intervals (ISIs) of 8,10 ms. There was no effect if the conditioning stimulus was applied 2.5 cm lateral, anterior or medial to dPM. The effect differed from previously described M1 interhemispheric inhibition in that the threshold for the latter was greater than 90% RMT, whereas stimulation of the dPM at the same intensity led to significant inhibition. In addition, voluntary contraction of the left FDI (i.e. contralateral to the conditioning TMS) enhanced interhemispheric inhibition from right M1 but had no effect on the inhibition from right dPM. Finally, conditioning to right dPM at 90% RMT reduced short-interval intracortical inhibition (SICI; at ISI = 2 ms) in left M1 whilst there was no effect if the conditioning stimulus was applied to right M1. We conclude that conditioning TMS over dPM has effects that differ from the previous pattern of interhemispheric inhibition described between bilateral M1s. This may reflect the existence of commissural fibres between dPM and contralateral M1 that may play a role in bimanual coordination. [source] 3243: In vivo quantitative measurement of oxidation repair of glutaredoxin-1ACTA OPHTHALMOLOGICA, Issue 2010PG SÖDERBERG Purpose Quantitative determination of the impact of glutaredoxin-1 on sensitivity to oxidative stress induced by in vivo exposure to ultraviolet radiation in the 300 nm wavelength region. Methods Altogether, 20 glutredoxin-1 knockout mice (Grx1 -/-) and 20 wild type C57BL/6, bred on the same background were in vivo exposed unilaterally to ultraviolet radiation in the 300 nm wavelength region (UVR-300 nm). For both the Grx1-/- and the Grx1+/+ groups, respectively, the animals were subdivided into 5 dose groups of four receiving 0.0, 2.1, 2.9, 3.6 or 4.1 kJ m^-2, depending on group belonging. At 48 hrs after exposure the animals were sacrificed, the lenses were extracted and measured for intensity of forward light scattering. The threshold dose for damage was estimated as the Maximum Tolerable Dose-2.3:16. The protection factor (PF), defined as the ratio between the threshold with protection and the threshold without protection was calculated. Results The MTD-2.3:16 was for the Grx1+/+ estimated to 3.81 kJ/m2 (95% CI, 2.82 , 6.37) and for the Grx1-/- estimated to 2.99 kJ/m2 (95% CI, 2.33 , 4.00). The PF factor for the Grx1 gene thus was 1.3. Conclusion The Grx-1 gene provides a higher tolerance to in vivo oxidative stress induced by in vivo exposure to ultraviolet radiation, allowing a 1.3 longer exposure times at the same intensity before cataract develops. [source] | |||||||||||||