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31.
Primary orthostatic tremor (POT) is a rare disorder characterised by an intense sense of unsteadiness upon standing and a 16-Hz tremor in which the timing between tremor bursts in different muscles (unilateral and bilateral) remains constant. Hitherto, similar EMG activity has not been described in healthy subjects and it has been postulated that the oscillations seen in POT are primarily pathological. In this study, EMG was recorded from tibialis anterior in healthy subjects who were made unsteady through vestibular galvanic stimulation or leaning backwards. Under these conditions, a peak at approximately 16 Hz was seen in the coherence between the left and right tibialis anterior. This bilateral coherence was absent when the subjects activated the same muscles when not unsteady. These data indicate the existence of a physiological system involved in organising postural responses under circumstances of imbalance and characterised by a highly synchronised output at approximately 16 Hz. In addition, the results suggest that the core abnormality in POT may be an exaggerated sense of unsteadiness when standing still, which then elicits activity from a 16-Hz oscillator normally engaged in postural responses. 相似文献
32.
Novel techniques have recently emerged to separate chiral drug compounds into pure enantiomers. The mechanism, experimental difficulties, and applicability of these methods can vary greatly, and the choices involved are not straightforward. The most significant new advances in the field of chiral separations have come from work done with liquid chromatographic systems and chiral stationary-phase columns. This review describes several commonly used approaches to chiral separation, diastereomeric derivatization, chiral mobile-phase additives, and three major types of chiral stationary phases. Although no single method can be judged superior for every drug application, it appears that chiral stationary phases have received the most attention recently and they are emphasized here. 相似文献
33.
Pui-Yin Lee Wai-Hong Chen William Ng Chu-Pak Lau 《Catheterization and cardiovascular interventions》2003,60(4):558-561
Subclavian artery lesion that is associated with low complication rate could be treated by percutaneous intervention effectively. However, the success of endovascular therapy for occlusive lesion may be limited by failure to cross with a guidewire. We describe the use of a system using optical coherence reflectometry for navigation and radiofrequency ablation to enable wire passage through subclavian artery occlusion that could not be crossed by conventional guidewires. 相似文献
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35.
BACKGROUND/AIMS: Hepatocytes (HEP) have been the major target for structural quantification in the liver, but an estimation of their total number (N), their percentage in relation to the global number of liver cells and the evaluation of the percentage of binucleated hepatocytes (BnHEPs) have never been performed with modern design-based stereological techniques. The establishment of sound technical guidelines and baseline quantitative data in non-pathological conditions are relevant to properly evaluate HEP hyperplasia and BnHEP responses. METHODS: In this study, we combined immunocytochemistry with sound design-based stereology for estimating the N of HEP and the N of non-hepatocytic cells (NHCs). For obtaining systematic uniform random sections (30 microm thick), a smooth fractionator sampling scheme was applied to the liver of five male Wistar rats (3 month old). Those sections were immunostained with polyclonal antibodies against carcinoembryonic antigen. Because biliary canaliculi were then marked, an unequivocal counting of mononucleated hepatocytes (MnHEP) and BnHEP was allowed. RESULTS: The N of HEP was estimated to be 1.93 x 10(9), with a coefficient of error (CE) of 0.02, corresponding to 129 x 10(6) HEP/g of liver. BnHEP represented 26% of total HEP number. The N of NHC was estimated as 1.31 x 10(9) (CE=0.02). CONCLUSION: The strategy here presented provides a reliable method for accessing the N of HEP (distinguishing MnHEP from BnHEP) in situations in which these parameters are relevant, namely for evaluating the magnitude of an hyperplastic liver response from its very early onset. 相似文献
36.
Roger A. Moore Anthony Gale Paul H. Morris Dave Forrester 《International journal of psychophysiology》2006,60(3):260-273
EEG theta coherence, EEG theta power and subjective levels of response were examined in a continuous monitoring target detection task where periodic goal conflicts were introduced as 34 participants progressed through a stimulus sequence leading to response. EEG theta coherence revealed increases in phase locking between cortical areas at specific task stages involving goal conflict. Theta power also increased at points of goal conflict. The temporal characteristics of subjective response (measured continuously throughout the task) indicated a delay between participants actually experiencing goal conflict and overt indications of conflict. The starting point for the study was based on a specific aspect of Gray and McNaughton's [Gray, J.A., McNaughton, N., 2000. The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-Hippocampal System, 2nd ed. Oxford University Press, Oxford] behavioural inhibition system model—namely, septo-hippocampal system involvement in the resolution of goal conflicts. We drew on Gray and McNaughton's [Gray, J.A., McNaughton, N., 2000. The Neuropsychology of Anxiety: An Enquiry into the Functions of the Septo-Hippocampal system, 2nd ed. Oxford University Press, Oxford] suggestion that septo-hippocampal involvement in this process is reflected by EEG theta. While their theory explains many of our findings, we also drew upon Given's [Givens, B., 1996. Stimulus-evoked reseting of the dentate theta rhythm: relation to working memory. Neuroreport 8 (1), 159–163] proposal that the dentate theta rhythm is reset by behaviourally relevant stimuli. We made further proposals based on Makeig et al.'s [Makeig, S., Westerfield, M., Jung, T.-P., Enghoff, S., Townsend, J., Courchesne, E., Sejnowski, T.J., 2002. Dynamic brain sources of visual evoked responses. Science 295, 690–694] view that specific stimulus events invoke concurrent phase resetting and transient frequency domain coherence across different areas of neocortex. Relations with Go/NoGo event related potentials (P300 and N2; e.g., [Bokura, H., Yamaguchi, S., Kobayashi, S., 2001. Electrophysiological correlates of response inhibition in a Go/NoGo task. Clin. Neurophysiol. 112 (12), 2224–2232]) were also discussed, as well as parallels between our data and interpretation, and other theoretical models of theta (e.g., [Kahana, M.J., Selig, D., Madsen, J.R., 2001. Theta returns. Curr. Opin. Neurobiol. 11, 739–744]). Suggestions for further research were made. 相似文献
37.
M. E. J. van Velthoven M. D. de Smet R. O. Schlingemann M. Magnani F. D. Verbraak 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2006,244(9):1119-1123
Background Evaluating the presence of leakage on fluorescein angiography (FA) in patients with age-related macular degeneration (AMD) retreated with photodynamic therapy (PDT) can be difficult. New diagnostic tools such as optical coherence tomography (OCT) might help to optimize PDT management.Methods Thirty AMD patients scheduled for regular follow-up FA in conjunction with PDT treatment were also scanned with OCT. Follow-up data at 9 months were retrieved from the patients’ medical records. Inter-observer agreement [kappa (κ) coefficient] for the presence of leakage on FA, for OCT parameters for leakage, and agreement between FA and OCT evaluations were calculated. The indication for retreatment was evaluated using the leakage analysis based on FA alone, OCT alone, and both examinations combined, and compared to the actual follow-up of the patients at 9 months.Results Agreement between the two observers for the presence of leakage on FA was moderate (κ=0.51). OCT agreement between the two observers for the presence of leakage was good (κ=0.85). Agreement between FA and OCT for the presence of leakage was poor (κ=0.16). Follow-up data at 9 months on all patients were analyzed. Seven out of 30 patients were not retreated at the time of examination, and four of these patients (57%) remained stable without further treatment. Twenty-three patients did receive a PDT treatment at the time of examination; and eight of these patients did not show leakage on OCT, and five of these patients (62%) remained stable without additional treatment. In contrast, only three out of 15 patients (20%) with leakage on both FA and OCT remained stable during this 9 month follow-up period.Conclusions Inter-observer agreement for the presence of leakage was moderate for FA and good for OCT. There was considerable disagreement between leakage as judged by OCT and by FA. OCT could be of help in the decision regarding PDT retreatment. Assuming that 57% of the patients without leakage either on FA or OCT would remain stable without retreatment, the rate of probable ineffective retreatment could be reduced from 35% to 20%.There was no financial support for this study. The authors have full access to the data and will allow Graefe’s Archive for Clinical and Experimental Ophthalmology to review the data if requeste.d 相似文献
38.
W. F. Harris 《Ophthalmic & physiological optics》2003,23(3):251-261
Traditional treatments of spectacle magnification for distant objects consider only stigmatic spectacle lenses and they compare the retinal image size in a refractively fully compensated eye with the image size in the uncompensated eye. Spectacle magnification is expressed as a product of two factors, the power and shape factors of the lens. The power factor depends on the position of the entrance pupil of the eye. For an eye with an astigmatic cornea, however, the position of the entrance pupil is not well defined. Thus, the traditional approach to spectacle magnification does not generalize properly to allow for astigmatism. Within the constraints of linear optics and subject to the restriction that the eye's iris remains the aperture stop, this paper provides a complete, unified and exact treatment for optical instruments in general. It compares retinal image size in a generalized sense (including image shape and orientation) for any instrument in front of an eye with that of the eye alone irrespective of whether the instrument compensates or not. The approach does not make use of the concept of the entrance pupil at all and it allows for astigmatism and for non-alignment of refracting elements in the instrument and in the eye. The concept of spectacle magnification generalizes to the concept of instrument size magnification. Instrument size magnification can be expressed as the product of two matrix factors one of which can be interpreted as a power factor (as back-vertex power) and the other factor for which the name dilation factor is more appropriate in general. The general treatment is then applied to a number of special cases including afocal instruments, spectacle lenses (including obliquely crossing thick bitoric lenses), contact lenses, stigmatic systems and stigmatic eyes. In the case of spectacle lenses, the dilation factor reduces to the usual shape factor. 相似文献
39.
外科手术对心肌缺血的血运重建是目前治疗心肌缺血性疾病的重要手段之一。术中准确判断心肌缺血范围及程度和严密监测心脏停跳后心肌细胞损伤是否加重,对于血运重建的准确性,更好地实施心肌保护及对手术疗效的评估和术后处理方案的拟定有着重要意义。因此,如何在术中判断心肌缺血的损伤程度和范围具有极为重要的实验研究意义与临床现实意义。光学相干层析成像作为一种新颖的成像技术,能对活体组织内部微小结构进行实时、在体、高分辨率断层成像。 相似文献
40.
Met and unmet nursing care needs in men with prostate cancer. An explorative study. Part II 总被引:1,自引:0,他引:1
LISELOTTE JAKOBSSON RNT INGALILL RAHM HALLBERG RNT PhD & LARS LOVÉN MD PhD 《European journal of cancer care》1997,6(2):117-123
Men with prostate cancer ( n = 11) were interviewed during an in-patient period at a urological clinic, about their experiences of met and unmet needs from health professionals. Their perception of quality of life and sense of coherence were also assessed. The findings were analysed from a phenemenological-hermeneutic perspective and interpreted within the concept of transition. It was interpreted that objective functional health needs were mostly met by health professionals and subjective existential needs were mostly not met. The analysis revealed patients as passive or active receivers of care. Passive receivers were explicitly and implicitly stating unmet needs, or explicitly stating satisfaction with nursing care at the same time as implicitly contradicting, referring to their needs as bagatelles, unimportant, whereas active receivers talked about their needs explicitly with the staff and did not state implicit unmet needs. This suggests that nurses need to be aware of and have sensitive ears to undertones in statements and actively seek for patients' needs. The most important nursing care areas seemed to be to provide solutions to physical problems together with staff support including information, and acting to increase confidence in staff and staff availability. This encourages patients, wives and families, in co-operation, towards a healthy exit of transition. 相似文献