声触诊组织定量技术鉴别诊断甲状腺微小癌的价值(英文)

目的:声触诊组织定量技术(VTQ)是一种新的弹性成像方法,能够定量、无创地评价组织硬度信息。本文的研究目的是探讨声触诊组织定量技术在鉴别诊断甲状腺微小癌(TMCs)中的应用价值。方法:应用VTQ技术对110例共114个结节(最大直径≤1 cm)进行检测,获取并分析结节及周边甲状腺组织的横向剪切波速度(SWV)。利用ROC曲线对测量结果进行分析,评价VTQ技术的诊断价值并确定最佳诊断界值。结果:114个结节中良性结节32个(30个为结节性甲状腺肿,2个为腺瘤),恶性结节82个(均为乳头状癌)。甲状腺良性结节及周边甲状腺组织的SWV平均值分别为(2.30±0.49)m/s、(2.08±0.40)m/s,恶性结节及周边甲状腺组织的SWV平均值分别为(3.12±0.97)m/s、(2.06±0.46)m/s。恶性结节的SWV值明显高于良性结节,两者之间差异具有统计学意义(t=5.911,P0.0001);恶性结节与其周边甲状腺组织比较有显著差异(P0.0001);而良性结节与其周边甲状腺组织无统计学差异(P0.05)。ROC曲线下面积为0.833,以2.30 m/s诊断界值点时,敏感度、特异度分别为90.2%、62.5%。结论:甲状腺恶性结节的SWV值明显高于良性结节。VTQ技术能够提供组织硬度信息,在鉴别诊断甲状腺微小癌方面具有一定的临床应用价值。     

Human alpha‐ and beta‐NRXN1 isoforms rescue behavioral impairments of Caenorhabditis elegans neurexin‐deficient mutants

Neurexins are cell adhesion proteins that interact with neuroligin and other ligands at the synapse. In humans, mutations in neurexin or neuroligin genes have been associated with autism and other mental disorders. The human neurexin and neuroligin genes are orthologous to the Caenorhabditis elegans genes nrx‐1 and nlg‐1, respectively. Here we show that nrx‐1‐deficient mutants are defective in exploratory capacity, sinusoidal postural movements and gentle touch response. Interestingly, the exploratory behavioral phenotype observed in nrx‐1 mutants was markedly different to nlg‐1‐deficient mutants; thus, while the former had a ‘hyper‐reversal’ phenotype increasing the number of changes of direction with respect to the wild‐type strain, the nlg‐1 mutants presented a ‘hypo‐reversal’ phenotype. On the other hand, the nrx‐1‐ and nlg‐1‐defective mutants showed similar abnormal sinusoidal postural movement phenotypes. The response of these mutant strains to aldicarb (acetylcholinesterase inhibitor), levamisole (ACh agonist) and pentylenetetrazole [gamma‐aminobutyric (GABA) receptor antagonist], suggested that the varying behavioral phenotypes were caused by defects in ACh and/or GABA inputs. The defective behavioral phenotypes of nrx‐1‐deficient mutants were rescued in transgenic strains expressing either human alpha‐ or beta‐NRXN‐1 isoforms under the worm nrx‐1 promoter. A previous report had shown that human and rat neuroligins were functional in C. elegans. Together, these results suggest that the functional mechanism underpinning both neuroligin and neurexin in the nematode are comparable to human. In this sense the nematode might constitute a simple in vivo model for understanding basic mechanisms involved in neurological diseases for which neuroligin and neurexin are implicated in having a role.     

A Sense of Belonging and Exclusion: ‘Touchability’ and ‘Untouchability’ in Tamil Nadu

In India, touch is a prime marker of status and social relations. Those who are impure are ‘untouchable’,1 The terms ‘Untouchable’ and ‘Untouchability’ have been abandoned due to the humiliating meaning these terms confer, therefore I use them in inverted commas. The politically correct and common terms today are Scheduled Castes, in short sc, or Dalits, or sometimes Harijan. I use them here synonymously. but those who are of a relatively higher purity are also, depending on the context, either ‘untouchable’ or ‘touchable’ only under certain fixed rules. In this paper, I will explore the contexts in which body contact and touch can be part of personal relations. I describe how these body contacts signify important social relations and establish community identity. Further, I will analyse how patterns of body contact on the one hand change during childhood, and on the other hand produce changes in the status of a social persona. The last point to be investigated is the meaning of touch as a sign for public representations.     

Spatial localization of electrotactile stimuli on the fingertip in humans

This study was designed to determine the extent to which sensations elicited by discrete electrotactile stimulation can be spatially localized, with a qualitative comparison to mechanical stimulation, in a 2 × 2 electrode array on the fingertip. Electrotactile stimulation was delivered in two modes: (1) same current to all locations (constant) or (2) current adjusted to perceptual threshold of each location (varied). For each stimulus location, subjects were asked to identify the location of the stimulus. Mechanical stimulation of the same locations on the fingerpad was delivered through von Frey hairs (0.07, 0.2 and 0.4 g). The percentage of accurate responses was computed for all stimulation modes. We found that the accuracy of discrimination of stimulus location in both the constant (46%%) and varied (40%%) electrotactile stimulation modes was significantly higher than chance level (25%%; p < 0.01). Furthermore, subjects were significantly more accurate in discriminating electrotactile stimuli in the constant than in the varied mode (p < 0.05). We also found that the accuracy of spatial discrimination was dependent on stimulation site for mechanical, but not electrotactile stimulation. Finally, we found a significant difference in accuracy over the duration of the experiment only for mechanical modes, which may indicate that electrotactile stimuli are less biased over time. These results suggest that, although low in accuracy, human subjects are able to extract spatial information from electrotactile stimuli. Further research is needed to optimize the amount of the information that can be delivered through electrotactile stimulation.     

Multiple parietal operculum subdivisions in humans: Tactile activation maps

We focused the present analysis on blood-oxygen-level-dependent responses evoked in four architectonic subdivisions of human posterior parietal operculum (PO) during two groups of tasks involving either vibrotactile stimulation or rubbing different surfaces against the right index finger pad. Activity localized in previously defined parietal opercular subdivisions, OP 1–4, was co-registered to a standard cortical surface-based atlas. Four vibrotactile stimulation tasks involved attention to the parameters of paired vibrations: (1) detect rare target trials when vibration frequencies matched; (2) select the presentation order of the vibration with a higher frequency or (3) longer duration; and (4) divide attention between frequency and duration before selecting stimulus order. Surface stimulation tasks involved various discriminations of different surfaces: (1) smooth surfaces required no discrimination; (2) paired horizontal gratings required determination of the direction of roughness change; (3) paired shapes entailed identifying matched and unmatched shapes; (4) raised letters involved letter recognition. The results showed activity in multiple somatosensory subdivisions bilaterally in human PO that are plausibly homologues of somatosensory areas previously described in animals. All tasks activated OP 1, but in vibrotactile tasks foci were more restricted compared to moving surface tasks. Greater spatial extents of activity especially in OP 1 and 4 when surfaces rubbed the finger pad did not support previously reported somatotopy of the second finger representation in “S2”. The varied activity distributions across OP subdivisions may reflect low-level perceptual and/or cognitive processing differences between tasks.     

Response properties of mouse trigeminal ganglion neurons

We used controlled whisker deflections to examine the response properties of 208 primary afferent neurons in the trigeminal ganglion of adult mice. Proportions of rapidly adapting (RA, 47%) and slowly adapting (SA, 53%) neurons were equivalent, and most cells had low or no spontaneous activity. We quantified angular tuning and sensitivity to deflection amplitude and velocity. Both RA and SA units fired more frequently to larger deflections and faster deflections, but RA units were more sensitive to differences in velocity whereas SA units were more sensitive to deflection amplitudes. Almost all neurons were tuned for deflection angle, and the average response to the maximally effective direction was more than fourfold greater than the average response in the opposite direction; SA units were more tuned than RA units. Responses of primary afferent whisker-responsive neurons are qualitatively similar to those of the rat. However, average firing rates of both RA and SA neurons in the mouse are less sensitive to differences in deflection velocity, and RA units, unlike those in the rat, display amplitude sensitivity. Subtle observed differences between mice and rats may reflect greater mechanical compliance in mice of the whisker hairs and of the tissue in which they are embedded.     

Recognition memory for vibrotactile rhythms: An fMRI study in blind and sighted individuals

Calcarine sulcal cortex possibly contributes to semantic recognition memory in early blind (EB). We assessed a recognition memory role using vibrotactile rhythms and a retrieval success paradigm involving learned “old” and “new” rhythms in EB and sighted. EB showed no activation differences in occipital cortex indicating retrieval success but replicated findings of somatosensory processing. Both groups showed retrieval success in primary somatosensory, precuneus, and orbitofrontal cortex. The S1 activity might indicate generic sensory memory processes.     

Ecomorphology reveals Euler spiral of mammalian whiskers

Whiskers are present in many species of mammals. They are specialised vibrotactile sensors that sit within strongly innervated follicles. Whisker size and shape will affect the mechanical signals that reach the follicle, and hence the information that reaches the brain. However, whisker size and shape have not been quantified across mammals before. Using a novel method for describing whisker curvature, this study quantifies whisker size and shape across 19 mammalian species. We find that gross two-dimensional whisker shape is relatively conserved across mammals. Indeed, whiskers are all curved, tapered rods that can be summarised by Euler spiral models of curvature and linear models of taper, which has implications for whisker growth and function. We also observe that aquatic and semi-aquatic mammals have relatively thicker, stiffer, and more highly tapered whiskers than arboreal and terrestrial species. In addition, smaller mammals tend to have relatively long, slender, flexible whiskers compared to larger species. Therefore, we propose that whisker morphology varies between larger aquatic species, and smaller scansorial species. These two whisker morphotypes are likely to induce quite different mechanical signals in the follicle, which has implications for follicle anatomy as well as whisker function.     

Touch sense: Functional organization and molecular determinants of mechanosensitive receptors

Cutaneous mechanoreceptors are localized in the various layers of the skin where they detect a wide range of mechanical stimuli, including light brush, stretch, vibration and noxious pressure. This variety of stimuli is matched by a diverse array of specialized mechanoreceptors that respond to cutaneous deformation in a specific way and relay these stimuli to higher brain structures. Studies across mechanoreceptors and genetically tractable sensory nerve endings are beginning to uncover touch sensation mechanisms. Work in this field has provided researchers with a more thorough understanding of the circuit organization underlying the perception of touch. Novel ion channels have emerged as candidates for transduction molecules and properties of mechanically gated currents improved our understanding of the mechanisms of adaptation to tactile stimuli. This review highlights the progress made in characterizing functional properties of mechanoreceptors in hairy and glabrous skin and ion channels that detect mechanical inputs and shape mechanoreceptor adaptation.