生理信号检测中的同步工频陷波器

市电50Hz干扰一直是生理信号检测过程中最难以克服的问题之一。本文叙述了利用同步滤波器技术克服50Hz干扰的方法。同步滤波器可以自动跟踪市电频率的变化且具有极高Q值和理想的梳状滤波特性,而元件的灵敏度却很低,因而很容易获得40dB以上的陷波效果,可以从根本上克服50Hz干扰而几乎对有用信号毫无影响。     

The use of 3D surface fitting for robust polyp detection and classification in CT colonography

In this paper we describe the development of a computationally efficient computer-aided detection (CAD) algorithm based on the evaluation of the surface morphology that is employed for the detection of colonic polyps in computed tomography (CT) colonography. Initial polyp candidate voxels were detected using the surface normal intersection values. These candidate voxels were clustered using the normal direction, convexity test, region growing and Gaussian distribution. The local colonic surface was classified as polyp or fold using a feature normalized nearest neighborhood classifier. The main merit of this paper is the methodology applied to select the robust features derived from the colon surface that have a high discriminative power for polyp/fold classification. The devised polyp detection scheme entails a low computational overhead (typically takes 2.20 min per dataset) and shows 100% sensitivity for phantom polyps greater than 5 mm. It also shows 100% sensitivity for real polyps larger than 10 mm and 91.67% sensitivity for polyps between 5 to 10 mm with an average of 4.5 false positives per dataset. The experimental data indicates that the proposed CAD polyp detection scheme outperforms other techniques that identify the polyps using features that sample the colon surface curvature especially when applied to low-dose datasets.     

Factors associated with recovery and recurrence of depression in older people: A prospective study

The Liverpool Continuing Health in the Community Study has followed up 1070 elderly community subjects over 6 years. In the first year 123 subjects had case-level depression. Three years later 49 (39.8%) of the previously depressed were recovered, 33 (26.8%) were depressed, 16 (13%) were not available for interview and 25 (20.3%) were dead. This study looks at factors associated with the 3-year outcome of patients who were depressed at year 0. Two outcome groups that were compared were a recovered depression group and a recurrent/persistent depression group. The factors that were significantly associated with a recurrence of depression (or persistent depression) at year 3 were bereavement of a close figure in the 6 months before interview, loneliness and life dissatisfaction at year 3. A variety of traditional risk factors for depression (including age, marital status, physical ill-health and incapacity) failed to attain significance in predicting recurrent or persistent depression. When combined, both recovered and recurrently depressed groups at year 3 had significantly higher levels of pain and a higher number of serious upsets in the past 6 months and 6 weeks compared to a compared to a control group. The depressed at year 0 were more likely to have entered more dependent forms of accommodation by year 3.     

Do discrepancies in interpersonal perception predict relapse?: A comparison of remitted depressed patients and collaterals

In an effort to examine whether disturbed interpersonal relationships are associated with relapse in depression, discrepancies in self-ratings provided by formerly depressed patients and their collateral informants were compared. Thirty-eight remitted depressed patients and their collateral informants were asked to monitor moods, life events, and stress levels on a bimonthly basis for a 1-year period. It was hypothesized that patient/collateral dyads displaying a greater discrepancy in interpersonal perception would have a higher risk of relapse than dyads who showed more agreement in their ratings. Results indicated that while discrepancies in the perceptions of patients' life events were associated with the duration of a relapse once it occurred, discrepancies were generally not related to the emergence of new episodes of depressive disorder. The implications of these findings for models seeking to integrate cognitive and interpersonal models of depression, through the study of environmentally determined and personally appraised adversity, is discussed.This research was supported by grants to the first and third authors from the Canadian Psychiatric Research Foundation and the Laidlaw Foundation.     

In vivo fluorescence spectroscopy and imaging of human skin tumours

The feasibility of using in vivo autofluorescence for the diagnosis of skin cancer was evaluated. In vivo fluorescence measurements were performed on healthy human volunteers, and patients with different types of benign and malignant skin tumours. Fluorescence spectra as well as fluorescence images were acquired. The excitation-emission matrix of normal skin (n=3) showed a broad peak at the shortest excitation wavelength (365 nm) and at 440 nm fluorescence wavelength, smoothly decreasing towards longer excitation and fluorescence wavelengths. Non-melanoma skin tumours (n=31) and control skin excited with 375 nm showed a broad fluorescence band from 400 to 700 nm, peaking around 436 nm. No significant differences in measurements between tumours and the corresponding control sites were found. A large spatial variation in the fluorescence intensity was observed both in the tumours and in the control sites. Standard deviations found ranged from 0.15 to 1.5 times the mean fluorescence. Fluorescence images, excited with 375 nm and taken with an image intensified CCD camera, on eight malignant melanomas and eight benign pigmented lesions did not indicate any fluorescence intensity distribution specific to the malignancy of the lesion. Neither the shape of the fluorescence spectra, nor the spatial distribution of the fluorescence intensity showed any signature specific to the histopathological nature of the lesions investigated. Optical diagnostics of skin tumours using the autofluorescence does not seem to be feasible at the present time.     

Outcome of surgery in patients with hematological malignancies: A 12-year retrospective analysis

Background: Surgical intervention in patients with malignant hematological disorders is a major undertaking due to the expected risks of bleeding, infection and poor wound healing. Methods and materials: A retrospective study of patients treated at the Riyadh Armed Forces Hospital, Saudi Arabia between January 1991 and December 2002 was conducted. The results of patients with acute leukemia and lymphoma who underwent surgical procedures (study group) were compared with those of a control group composed of patients with the same spectrum of disorders treated over the same period of time and given the same treatment protocols but never required any surgery. Results: No single death occurred intraoperatively or in the immediate postoperative period due to surgical therapy per se. However, follow up of both groups of patients revealed a shorter long‐term survival and higher rates of relapse and severe invasive infections in the surgical group compared to the control group of patients. The mean survival for the study group was 1871 ± 307 days versus 3094 ± 279 days for the control group of patients (P = 0.0027). Thirty (75%) study patients suffered relapses of their malignant hematological disorders versus 23 (37.1%) control patients. Forty‐five relapses were encountered in the study group of patients (1.5 relapses per relapsed patient) versus 26 relapses in the control group (1.13 relapses per relapsed patient). Various infections occurred in 37 (92.5%) study patients and 32 (51.6%) control patients. Recurrent infections developed in 30 (75%) study patients and 22 (35.5%) control patients (P = 0.00008). Infections causing tissue invasion were encountered in 29 (72.5%) study patients and 22 (35.5%) control patients. Conclusion: Even major surgical procedures can be performed in patients with leukemia or lymphoma provided enough preparatory measures are made to minimize bleeding and infectious complications. Surgery may, however, be associated with long‐term complications such as a high incidence of relapse of the primary malignant hematological disorder and an increased rate of severe and invasive infections.     

Comparison of redox and D29 phage methods for detection of isoniazid and rifampicin resistance in Mycobacterium tuberculosis

Rapid, accurate and inexpensive methods are essential to detect drug-resistant Mycobacterium tuberculosis and allow timely application of effective treatment and precautions to prevent transmission. The proportion method, the MTT and Alamar Blue redox methods, and the D29 mycobacteriophage assay, were compared for their ability to detect resistance to isoniazid and rifampicin. When tested against a panel of known M. tuberculosis strains, the redox methods and the D29 assay showed good sensitivity and specificity compared to the proportion method, suggesting that they could be useful alternatives for identifying multidrug resistance in M. tuberculosis.     

Aripiprazole blocks reinstatement of cocaine seeking in an animal model of relapse.

BACKGROUND: Aripiprazole (Abilify) is an atypical antipsychotic drug primarily characterized by partial agonist activity at dopamine (DA) D2 receptors and low side effects. Based on pharmacologic properties that include a stabilization of mesocorticolimbic DA activity, a pathway implicated in addiction, aripiprazole was tested for its ability to prevent relapse to cocaine seeking in rats. METHODS: We assessed the dose-dependent effects of aripiprazole on conditioned cue-induced and cocaine-primed reinstatement of drug-seeking behavior following chronic intravenous cocaine self-administration in an animal model of relapse. RESULTS: Aripiprazole potently and dose-dependently attenuated responding on the previously cocaine-paired lever during both reinstatement conditions, with slightly greater efficacy at reducing conditioned-cued reinstatement. Aripiprazole was effective at doses that failed to alter cocaine self-administration, food self-administration, reinstatement of food-seeking behavior, or basal locomotor activity, suggesting selective effects of aripiprazole on motivated drug-seeking behavior. CONCLUSIONS: These results in a relapse model show that aripiprazole can block cocaine seeking without affecting other behaviors. The D2 partial agonist properties of aripiprazole likely account for the blockade of reinstatement of cocaine-seeking behavior. Given its established efficacy and tolerability as a treatment for psychosis, aripiprazole may be an excellent therapeutic choice for reducing craving and preventing relapse in people with cocaine dependency.     

Optimising Hormone Therapy in Advanced Disease

Although most prostate cancer (PCa) patients nowadays are diagnosed at an early stage of disease, unfortunately still a significant number of patients will develop advanced PCa or will be diagnosed at an advanced (or metastatic) stage of disease. The group of patients showing the highest increase in incidence are those with rising prostate specific antigen (PSA) after radical therapy.In the last quarter of 2004, a Medline search has been performed targeting publications on patients diagnosed with advanced PCa, as well as with PSA relapse after previous radical therapy. This review aims at providing guidance to optimise hormone therapy in those selected groups of patients by addressing three pivotal questions; (i) who should receive hormonal treatment, (ii) what type of hormonal therapy should the patient be offered and (iii) what is the best timing of starting hormonal treatment.In patients relapsing after radical therapy, the PSA doubling time (PSA DT) has become a critical instrument to distinguish patients to have innocuous PSA evolution from patients at high risk for disease progression. A PSA DT of 3 months seems to be the cut-off point for identifying patients at risk. Therefore patients with a PSA DT of less than 3 months should be advised to initiate hormonal therapy. Antiandrogen monotherapy may be considered in this setting as it has been shown to delay progression; however, significant survival data are not yet available. Whether luteinising hormone releasing hormone (LHRH) agonists should be given continuously or intermittently (IHT) remains subject of debate.Surgical castration has been the standard of care in patients diagnosed with advanced PCa. Currently, LHRH agonists have become the preferred way of suppressing testosterone.Combination of an antiandrogen and a LHRH agonist (CAB) shows a modest benefit over LHRH agonist monotherapy. As CAB leads to increased side effects and costs, LHRH agonist monotherapy is preferred in the majority of patients.Conflicting data have been published concerning the optimal timing of LHRH agonist therapy. So it is not clear whether LHRH agonist therapy should be started immediately or deferred until appearance of symptoms. When initiating continuous hormone therapy, patients should be carefully monitored for the risk of long term androgen deprivation (anaemia, osteopenia and osteoporosis).