High-resolution fragmentary decomposition--a model-based method of non-stationary electrophysiological signal analysis

Fragmentary decomposition (FD) is a recently developed method of non-stationary electrophysiological signal analysis addressed to mass potentials, such as electromyogram (EMG), event-related potential (ERP), evoked potential, electroencephalogram (EEG), electroretinogram, etc. Being supported by the generally accepted physiological notion that a peak is a functionally meaningful component of a mass potential, FD provides a way to avoid averaging and, instead, quantifies the component composition of complex electrophysiological signals directly from single-trials. The major computational procedures of FD include adaptive segmentation, the frequency domain component identification, and creation of the signal model as a linear aggregation of multiple components, with the generic mass potential (GMP) being the universal component template. This paper presents an improved, high-resolution FD technique which allows the resolution of overlapping sub-components and supports each identified component by an individual model. On the basis of this methodological innovation, we define two fundamental categories of multi-peak component waveforms: complex components (CC), comprised of multiple sub-components (GMPs), versus monolithic components (MC), involving a single GMP. We show that quantification of MCs and CCs from single-trial eyeblink EMG and single-trial ERP provides a more comprehensive analysis of these signals. Given single-trial eyeblink EMG, we find that the stimulus elicits strong though short-term (phasic) effects on MCs and moderate but long-lasting (tonic) effects on CCs. A new realm of single-trial ERP quantification is possible in that the MC appears as a marker of a single cognitive variable whereas the CC appears as a marker of a series of functionally related cognitive variables. The engagement of the brain in a specific cognitive task is accompanied by an increase of CCs in single-trial ERPs, which is especially informative with respect to the P3 cognitive potential. New methodology provides evidence for the three basic types of single-trial P3 sub-components: monolithic P3a, monolithic P3b, and a complex component, P3ab, which includes both P3a and P3b as sub-components.     

糖稳态调节细胞定向分化的基因改造方案探讨

目的:探索糖稳态调节细胞定向分化的基因改造方案思路.方法:①研究构建的解除干细胞分化抑制状态的信号传导与转录激活因子-3(STAT-3)基因载体,检测其介导目的基因感染ARIP等细胞基因表达;②研究构建的活化配体DL诱导N信号、在"旁侧抑制"过程中扮演重要角色的Kuzbanian(KUZ)基因载体在转基因小鼠表达后糖稳态调节细胞的分化.结果:在完成的STAT-3腺病毒基因载体生产了腺病毒,用带有目的基因的腺病毒对ARIP靶细胞进行感染,3 d后,荧光显微镜观察时,活细胞、固定液固定细胞均看到了构建基因中绿色荧光蛋白成功、高效的阳性表达报告.在完成的Kuzbanian(KUZ)基因载体构建、转基因、动物模型、小鼠品系鉴定后,用非放射性原位杂交实验对胰腺靶细胞的mRNA进行检测,获得了预期的阳性结果.结论:通过用某些分化抑制性基因的显性失活形式(DN)竞争性预先解除干细胞分化的抑制状态,然后再定向分化诱导使之朝向期望的目标细胞方向分化,可能是糖稳态细胞定向分化的可行途径之一.     

Osteochondroma of the cervical spine--a surprising finding in a liver transplanted patient with polyneuropathy and polyradiculitis: case report

BACKGROUND: Osteochondroma of the spine is a rare condition. We report a case of a patient with a cervical osteochondroma presenting with a polyneuropathy and polyradiculitis simultaneously. CASE DESCRIPTION: In a liver-transplant patient with progressive neurological deficits a polyneuropathy and a polyradiculitis were diagnosed. Eventually the patient became quadraparetic and an osteochondroma compressing the cervical spinal cord was found. The patient's neurological symptoms markedly improved after gross total tumor resection and antibiotic therapy. CONCLUSIONS: Review of the literature reveals this case to be an unusual presentation of a cervical osteochondroma, its diagnosis being delayed because of concomitant neurological diseases.     

Physiological anticoagulants and activated protein C resistance in childhood stroke

Immunological and functional protein S, protein C and antithrombin III levels and anticoagulant responses to activated protein C were measured in 24 patients with stroke in childhood. No hereditary deficiencies were found. The protein S levels in healthy controls of younger age did not differ from the adult levels. For optimal screening of protein S deficiency, measurements using functional as well as immunological assays are recommended. Appropriate criteria for the diagnosis of the deficiencies must be carefully applied if unnecessary anxiety and inappropriate treatment of children are to be avoided.     

Non-invasive detection of fecal protein kinase C betaII and zeta messenger RNA: putative biomarkers for colon cancer

We have developed a non-invasive method utilizing feces, containing sloughed colonocytes, as a sensitive technique for detecting diagnostic colonic biomarkers. In this study, we used the rat colon carcinogenesis model to determine if changes in fecal protein kinase C (PKC) expression have predictive value in monitoring the neoplastic process. Weanling rats were injected with saline or azoxymethane (AOM) and 36 weeks later fecal samples and mucosa were collected, poly A+ RNA isolated, and quantitative RT-PCR performed using primers to PKC betaII and zeta. Fecal PKC betaII and zeta mRNA levels were altered by the presence of a tumor, with tumor-bearing animals having a 3-fold higher (P < 0.05) PKC betaII expression as compared with animals without tumors. In addition, AOM-injection increased mucosal PKC betaII mRNA expression compared with saline controls. No effect of tumor incidence on mucosal PKC betaII expression was observed. In contrast, fecal PKC zeta expression was 2.5-fold lower (P < 0.05) in animals injected with azoxymethane versus saline. Since tumor incidence exerts a reciprocal effect on fecal PKC betaII and zeta mRNA expression, data were also expressed as the ratio between PKC betaII and zeta. The isozyme ratio was strongly related to tumor incidence, i.e. ratio for animals with tumors was 2.18 +/- 1.25, animals without tumors was 0.50 +/- 0.16, P = 0.025. We demonstrate that the expression of fecal PKC betaII and zeta may serve as a noninvasive marker for development of colon tumors. A sensitive technique for the detection of colon cancer is of importance since early diagnosis can substantially reduce mortality.      

Status of clinical research in academic health centers: views from the research leadership

CONTEXT: The changing state of the health care system in the United States may be adversely affecting clinical research conducted in academic health centers (AHCs). Few formal data have been gathered about the nature and extent of the problems facing clinical research or the effects of remedies undertaken by AHCs. OBJECTIVES: To assess the perceived quality and health of the clinical research enterprise and to determine challenges and adaptations to current environmental pressures. DESIGN, SETTING, AND PARTICIPANTS: Mailed survey conducted between December 1998 and March 1999 of a subsample of department chairs and senior research administrators (SRAs) in all US medical schools. Of the 712 potential respondents, 478 completed a questionnaire, yielding an overall response rate of 67.1% (64.8% for SRAs and 67.8% for department chairs). MAIN OUTCOME MEASURES: Ratings of overall health/robustness of clinical research, quality of research in 5 domains, extent of challenges to performing research, and sense of urgency in responding to research challenges; formal strategies for research-related tasks and their effects. RESULTS: Slightly more than half (52%) of all respondents rated the health of the clinical research enterprise as good or excellent compared with 63% for nonclinical research (P<.001). Respondents were most likely to rate nonclinical research as high in quality (79%) compared with 70% for phase 3 clinical trials, 67% for translational research, 65% for phase 1 and 2 trials, and 57% for health services research (for all comparisons with nonclinical research, P<.001). Pressure on clinical faculty to see patients was perceived as a moderate-to-large problem for clinical research by the largest percentage of respondents (93%), followed by insufficient clinical revenues (89%), recruiting trained researchers (75%), lack of external support for clinical research (72%), competition from contract research organizations (48%), problems introduced by the institutional review board process (38%), and finding research participants (37%). In total, 81% of respondents considered the challenges facing clinical research in AHCs to be urgent or extremely urgent. CONCLUSIONS: Academic leaders perceive clinical research activities in AHCs to be less healthy, of poorer quality, and facing greater challenges than nonclinical research activities. Many AHCs do not have policies or mechanisms to address challenges facing the clinical research mission. Even among those with such policies, more than half do not believe these policies have had large positive effects. Our findings support the view that the clinical research workforce and infrastructure may need to be expanded and strengthened to keep pace with advances in basic research.     

Bell's palsy: Surgery based upon prognostic indicators and results

We studied 164 patients with Bell's palsy prospectively over the six-year period between August 1974 and June 1980. We found that the results of measuring tear production, sub-mandibular salivary flow, the response to maximal stimulation, and evoked electromyography gave us sufficient information to group these patients according to prognosis —either unfavorable or favorable — for spontaneous return of facial function. When the test results were 26% or more of normal, 90% of the patients had complete recovery of function; these patients were given a favorable prognosis on the basis of the results of tests described above. The natural history of Bell's palsy in patients with an unfavorable prognosis could be improved if a transmastoid facial nerve decompression to the labyrinthine segment were performed. The results were better with this approach than with supportive or steroid therapy or transmastoid vertical-horizontal surgical decompression of the facial nerve.