Overexpression of nerve growth factor in skin causes preferential increases among innervation to specific sensory targets

The impact of increased levels of skin-derived nerve growth factor (NGF) neurotrophin on sensory and sympathetic innervation to the mouse mystacial pad and postero-orbital vibrissae was determined. Consistent with an approximate doubling of neuron number in trigeminal and superior cervical ganglia, many components of the sensory and sympathetic innervation were substantially enhanced. Although the increased number of neurons raised the possibility that all types of innervation were increased, immunohistochemical analysis indicated that enhanced NGF production had a differential effect upon sensory innervation, primarily increasing unmyelinated innervation. This increased innervation occurred in specific locations known to be innervated by small, unmyelinated fibers, suggesting that NGF modulated sensory innervation density, but not targeting. In contrast, sympathetic innervation was not only increased but also was distributed to some aberrant locations. In the intervibrissal fur of the mystacial pad, both the number of sensory axons and branches appeared increased, whereas in vibrissal follicle sinus complexes, only branching increased. In some areas, sensory ending density was lower than expected based upon the size of the source nerve bundles suggesting that many axons and branches were surviving but failing to form functional endings. Furthermore, the immunochemical profile of innervation was altered in some sensory populations as demonstrated by the coexistence of RT-97 neurofilament labeling in calcitonin gene-related peptide (CGRP) positive axons, by the loss of substance P colocalization in some CGRP axons, and by an absence of neuropeptide Y labeling in tyrosine hydroxylase positive sympathetic axons. Collectively, these results indicate that the NGF mediated increase in neuron number may be selective for particular sets of innervation and that increases among some populations may result from phenotypic switching.     

Improving patient care by reporting problems with medical devices

Healthcare practitioners are the primary users of medical devices for direct patient care. As such, they are in the best position to recognize problems that result from the use of medical devices. The outcome of a device-related adverse event or product problem, as with any other medical product, can be serious and result in illness injury, or even death. The sooner that FDA learns about a problem, the sooner the agency can take action to protect patient and user safety. Healthcare practitioners are major contributors to the knowledge base related to device use and safety through astute monitoring, rapid identification of device-related problems, and reporting these problems. An understanding of the voluntary and mandatory mechanism of reporting will ensure that device problems are reported appropriately and in a timely manner. As the primary users of medical equipment for direct patient care, health care professionals have the training and expertise to improve patient care by reporting actual and suspected problems with medical devices.     

Comparison of IL-10 levels in chronic venous insufficiency ulcers and autologous donor tissue

In previous immunohistochemical studies, chronic venous insufficiency (CVI) ulcers have been shown to display positive staining for interleukin-10 (IL-10), while other wounds (including autologous donor wound tissue) show a reduced staining level. IL-10 inhibits the synthesis of many proinflammatory cytokines, while also inhibiting antigen presentation by antigen-presenting cells. It is possible that abnormally high amounts of IL-10 in chronic wounds may be related to the failure of these wounds to progress to final wound healing. The purpose of this study was to quantify the levels of IL-10 in CVI ulcers and autologous donor tissue using Western blotting. Extracts were prepared from frozen wound tissue samples and equal amounts of protein were concentrated by immune-precipitation for Western blot analysis. Densitometric analysis was performed on nonsaturated chemilumigraphs and normalized to an IL-10 standard run on each gel. The quantity of IL-10 in CVI ulcers was found to be 490% of the quantity in autologous donor tissue. This study provides confirmatory quantitative data which supports previous immunohistochemical findings showing elevated levels of IL-10 in CVI ulcers.     

Cryptosporidiosis in persons with HIV infection

Cryptosporidium parvum is an ubiquitous protozoan parasite that is a major cause of diarrhoea in individuals infected with human immunodeficiency virus. The hallmarks of infection include profuse watery diarrhoea which may become chronic in the severely immunosuppressed individual. No uniformly effective therapy exists. Current treatment relies upon a trial of anti-retroviral and specific anti-cryptosporidial medications, adequate fluid and nutritional support, and anti-motility agents.     

Dual X-ray absorptiometry quality control: comparison of visual examination and process-control charts

Dual X-ray absorptiometry (DXA) is widely used to monitor treatment efficacy in reducing the rate of bone mineral loss. In order to assure the validity of these measurements, instrument quality control of the DXA scanners becomes very important. This paper compares five quality control procedures (visual inspection, Shewhart chart with sensitizing rules, Shewhart chart with sensitizing rules and a filter for clinically insignificant mean changes, moving average chart and standard deviation, and cumulative sum chart [CUSUM]) in their ability to identify scanner malfunction by means of (1) an analysis of five longitudinal phantom data sets that had been collected during a clinical trial and (2) an analysis of simulated data sets. The visual inspection method is relatively subjective and depends on the operator's experience and attention. The regular Shewhart chart with sensitizing rules has a high false alarm rate. The Shewhart chart with sensitizing rules and an additional filter for clinically insignificant mean changes has the lowest false alarm rate but a relatively low sensitivity. The CUSUM method has good sensitivity and a low false alarm rate. In addition, this method provides an estimate of the date a change in the DXA scanner performance might have occurred. The method combining a moving average chart and a moving standard deviation chart came closest to the performance of the CUSUM method. Comparing the advantages and disadvantages of all methods, we propose the use of the CUSUM method as a quality control procedure for monitoring DXA scanner performance. For clinical trials use of the more intuitive Shewhart charts may be acceptable at the individual sites provided their scanner performance is followed up by CUSUM analysis at a central quality assurance center.     

深亚微米MOSFET模型研究进展

文中对在深亚微米ＭＯＳＦＥＴ的器件模型研究基础上，提出了研究ＭＯＳＦＥＴ模型值得注意的问题，并对如何建立深亚微米ＭＯＳＦＥＴ模型作出了有益的探讨。