薄层色谱法在当前中药质量标准中的应用探讨

薄层色谱鉴别在历版《中国药典》中的应用经历了从无到有、从少到多的过程；而薄层扫描含量测定在最近几版《中国药典》中的应用比例逐渐降低。随着对中药质量标准体系要求的进一步提高，薄层色谱法的不足之处陆续显现，如仪器普及率低、设备并不简单、结果重复性和稳定性较差、鉴别速度及准确性不及高效液相色谱法、展开剂毒性大等，逐渐不合时宜。在制定中药质量标准时，研究者不应该墨守成规，薄层色谱鉴别也不应该是雷打不动的定性鉴别必备选项。高效液相色谱法具备完全取代薄层色谱法的可行性，薄层色谱法可作为高效液相色谱法的补充。为充分降低检测成本、缩短检测周期、提高鉴别效率，笔者建议中药质量标准体系应该大幅减少薄层色谱鉴别方法的应用，增加高效液相特征图谱鉴定，尽量做到“一个条件，一张图谱”；除非确有必要，《中国药典》等国家质量标准体系应将薄层色谱鉴别作为推荐方法，而非强制标准。     

International Hand Function Study Following Distal Radial Access: The RATATOUILLE Study

BackgroundDistal radial access (DRA) has been proposed to improve procedure ergonomics and favor radial artery patency. Although promising data, nothing is known on evolving hand function after DRA.ObjectivesThis study sought to comprehensively evaluate hand function in patients undergoing DRA.MethodsReal-world patients undergoing DRA undertook a thorough multimodality assessment of hand function implementing multidomain questionnaires (Disabilities of the Arm, Shoulder and Hand and Levine-Katz), and motor (pinch grip test) and sensory (Semmes-Weinstein monofilaments test) examinations of both hands. All assessments were performed at preprocedural baseline and planned at 1-, 6-, and 12-month follow-up (FU). Adverse clinical and procedural events were documented too.ResultsData of 313 patients (220 men, age 66 ± 10 years) from 9 international centers were analyzed. The Disabilities of the Arm, Shoulder and Hand and the Levine-Katz scores slightly improved from baseline to FU (P = 0.008 and P = 0.029, respectively). Pinch strength mildly improved from baseline to FU (P < 0.001 for both the left and right hands). Similarly, touch pressure threshold appeared to faintly improve in both the left and right hands (P < 0.012 for all the sites). For both motor and sensory function tests, comparable findings were found for the DRA hand and the contralateral one, with no significant differences between them. Repeated assessment of all tests over all FU time points similarly showed lack of worsening hand function. Access-related adverse events included 19 harmless bleedings and 3 forearm radial artery and 3 distal radial artery occlusions. None affected hand function at FU.ConclusionsIn a systematic multidimensional assessment, DRA was not associated with hand function impairment. Moreover, DRA emerges as a safe alternative vascular access.     

Pseudoathetosis: report of three patients.

We report on 3 patients with pseudoathetosis, which are involuntary, slow, writhing movements due to loss of proprioception.     

Nonlinear sensory cortex response to simultaneous tactile stimuli in writer's cramp.

Writer's cramp is a task-specific dystonia that leads to involuntary hand postures during writing. Abnormalities of sensory processing may play a pathophysiological role in this disorder. Electrophysiology studies in a monkey model of focal dystonia have revealed de-differentiation of sensory maps and the existence of single cells in hand regions of area 3b with enlarged receptive fields that extend to the surfaces of more than one digit. These changes may lead to abnormal processing of simultaneous sensory inputs. To study abnormal processing of simultaneous sensory information in adult humans with writer's cramp, we used functional magnetic resonance imaging to compare the response in primary sensory cortex with simultaneous tactile stimulation of the index and middle finger, with the response to stimulation of each finger alone. We tested five patients with writer's cramp and seven unaffected (normal) subjects. In the normal subjects, a linear combination of the activation patterns for individual finger stimulation predicts the pattern of activity for combined stimulation with 12% error. In writer's cramp patients, the linear combination predicted the combined stimulation pattern with 30% error. Results indicate a nonlinear interaction between the sensory cortical response to individual finger stimulation in writer's cramp. This altered interaction may contribute to the motor abnormalities.     

Are the same phoneme and lexical layers used in speech production and comprehension? A case-series test of model of aphasic speech production

In this paper, we investigate the claim that although the same lexical units are involved in speech production and comprehension, there are separate input and output phoneme layers (Foygel and Dell, 2000). Data from a case series of aphasic patients are used to test this claim by examining the relationship between performance on a test of picture naming and performance on tests of phonological input. Estimates of each patient's semantic-lexical and phonological impairments in speech production were derived from Foygel and Dell's computational model of picture naming. It was found that the strength of the semantic-lexical impairments in speech production was significantly correlated with performance on auditory comprehension tests. This finding is consistent with the claim that the same lexical units are involved in speech comprehension and production. Conversely, the correlations between the strength of the phonological lesions in speech production and performance on tests of phonological input were non-significant, consistent with Foygel and Dell's claim that there are distinct input and output phoneme layers.     

Morphology of corticotectal cells in the primary visual cortex of hooded rats

In primary visual cortex of hooded rats, pyramidal cells in layer V may be classified as long, medium, or short, on the basis of the layer in which the apical dendrite terminates. The present study determines which of these types of pyramidal cells project to the superior colliculus. Two different strategies were used to label corticotectal cells with horseradish peroxidase (HRP). In the first set of experiments, a large number of corticotectal cells were labeled by retrograde transport following injection of HRP into the superior colliculus. In the second set of experiments, single unit recording was used to identify corticotectal cells physiologically by antidromic activation from the superior colliculus. These cells were then impaled and labeled by intracellular iontophoresis of HRP. The results from both techniques suggest that only long pyramidal cells send an axon to the superior colliculus. These cells are distinguished by an apical dendrite that extends into layer I. We conclude that in hooded rats corticotectal cells in primary visual cortex are the long pyramids in layer V.     

pp60c-src encoded by the proto-oncogene c-src is a product of sensory neurons

The advent of recombinant DNA technology has led to the identification in the DNA of normal animal cells of over 30 proto-oncogenes that are homologous to retroviral transforming genes. One of these encodes a protein kinase (pp60c-src) of unknown function, that is preferentially synthesized in brain and neural retina. Here the expression of pp60c-src in the peripheral nervous system was examined in sensory neurons from chick dorsal root ganglia with antisera raised against the transforming protein of Rous sarcoma virus (pp60v-src) expressed in Escherichia coli carrying the cloned v-src gene. This antiserum recognizes pp60c-src specifically in normal chicken cells. Western immunoblotting showed that dorsal root ganglia of stage 30 (day 6.5) chick embryos contained elevated levels of pp60c-src. Immunoperoxidase staining of neuron-enriched cultures prepared from chick dorsal root ganglia showed pp60c-src immunoreactivity in cells with neuronal morphology; flat, fibroblastic cells contained no detectable immunoreactivity. Indirect double immunofluorescence with pp60src antibodies and monoclonal antibodies against the 200-kD subunit of neurofilament protein confirmed that the cells expressing pp60c-src were neurons. Ninety-six percent of the neurofilament-positive cells were immunoreactive with pp60src antibodies, and conversely, all pp60c-src-positive cells were immunoreactive with neurofilament antibodies. pp60c-src immunofluorescence appeared to be distributed over the cell body, processes, and growth cones. These results clearly demonstrate that pp60c-src is a product of neurons and is expressed in sensory neurons in culture.