Selection of DNA binding sites for zinc fingers using rationally randomized DNA reveals coded interactions.

In the preceding paper [Choo, Y. & Klug, A. (1994) Proc. Natl. Acad. Sci. USA 91, 11163-11167], we showed how selections from a library of zinc fingers displayed on phage yielded fingers able to bind to a number of DNA triplets. Here, we describe a technique to deal efficiently with the converse problem--namely, the selection of a DNA binding site for a given zinc finger. This is done by screening against libraries of DNA triplet binding sites randomized in two positions but having one base fixed in the third position. The technique is applied here to determine the specificity of fingers previously selected by phage display. We find that some of these fingers are able to specify a unique base in each position of the cognate triplet. This is further illustrated by examples of fingers which can discriminate between closely related triplets as measured by their respective equilibrium dissociation constants. Comparing the amino acid sequences of fingers which specify a particular base in a triplet, we infer that in most instances, sequence-specific binding of zinc fingers to DNA can be achieved by using a small set of amino acid-nucleotide base contacts amenable to a code.     

Occurrence of different genospecies ofBorrelia burgdorferi sensu lato in ixodid ticks of Valais,Switzerland

A total of 825 adult ticks (727Ixodes ricinus, 72Dermacentor marginatus and 26Haemaphysalis punctata) was collected from vegetation in Valais (Switzerland) in 1987 to 1992. They were examined for the presence ofBorrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis.B. burgdorferi sensu lato was detected by indirect immunofluorescence assay, dark field microscopy and/or culture in 221 out of 727I. ricinus (30.4%) and none in the other two species. From these 221 infected ticks we obtained 50 isolates. Indirect immunofluorescence assay and culture were used for all ticks but dark field examination has also been performed and compared to the two above mentioned methods for 231I. ricinus. Indirect immunofluorescence was found the most efficient method for the detection of Borrelia in ticks with 54 positive out of 231, followed by dark field examination with 35 positive and culture with 12 isolates. We found no site free of Borrelia whereI. ricinus is present. The rate of infection varied from 9.7 to 47.5%, as detected by the addition of the three methods. Typing of the 50 isolates revealed also a nonhomogeneous distribution of the Borrelia species. Based on the electrophoretic mobility of the OspA and B and immunostaining with species specific monoclonal antibodies (H3TS forB. burgdorferi sensu stricto, D6 forB. garinii and J8.3 forB. afzelii) 4 groups could be observed. Half of the isolates (n=26) were typed asB. burgdorferi sensu stricto, 19 asB. garinii, 3 asB. afzelii and 2 as group VS116. This forth group formed of two isolates from one location is genetically distinct from the 3 former species described in Europe so far. The Borreliae of this group are unreactive with any of the three monoclonal antibodies used.     

Use of patient satisfaction data in a continuous quality improvement program for endoscopic sinus surgery.

OBJECTIVE: Continuous quality improvement (CQI) is an effort by health care providers to improve the quality of service by continuously exceeding patients' expectations. Patient satisfaction is one of the measures of the quality of care. The aims of this study were to report the patients' evaluation of endoscopic sinus surgery (ESS) and to explore the feasibility in using patient satisfaction data in the CQI program for ESS. METHODS: Eighty-three patients completed a validated patient satisfaction survey (PSS) 1 month after undergoing ESS. Logistic regression models were applied to determine the confounders of patient satisfaction. RESULTS: In general, 72% of patients were very satisfied with the services. Education level and milder disease correlated with higher overall satisfaction levels (P 相似文献   

Molecular pattern and antimicrobial susceptibility of methicillin-resistant Staphylococcus aureus isolates at a teaching hospital in Northern Taiwan.

BACKGROUND AND PURPOSE: Methicillin-resistant Staphylococcus aureus (MRSA) infection has progressively increased worldwide. Knowledge of the specific epidemiological pattern of isolates at individual hospitals is important. METHODS: MRSA bacteremia was diagnosed in a total of 68 patients from January 2002 through December 2003, stratified for drug susceptibility and molecular pattern (staphylococcal cassette chromosome mec element [SCCmec] typing and genotypes). RESULTS: SCCmec-A-positive isolates were found on polymerase chain reaction in 58 patients. The most frequent SCCmec types were III (40 cases) of which less than 5% were susceptible to other beta-lactam antibiotics and most were health care-associated, followed by SCCmec type IV (15 cases), that were demonstrated to be community-acquired. SCCmec type IV MRSA isolates were more likely to be susceptible to ciprofloxacin (93.3%), gentamicin (46.7%) and trimethoprim-sulfamethoxazole (93.3%) than type III isolates. All MRSA isolates were susceptible to glycopeptides and vancomycin (minimum inhibitory concentrations <2 microg/mL). Pulsed-field gel electrophoresis with SmaI digestion was used to fingerprint these isolates. A total of 9 genotypes with 26 type-subtypes were identified. Genotype A was the most frequent (9 subtypes) indicating that it is epidemic in this hospital. CONCLUSION: After analysis, SCCmec typing could be used to predict drug susceptibility. Specific clones of S. aureus are circulating in hospital and communities in Taiwan.     

Left posterior fascicular tachycardia due to localized microreentry

Fascicular tachycardia in young patients without overt heart disease constitutes a rare but electrophysiologically distinct arrhythmia entity. Microreentry within the left posterior fascicle has been proposed as its mechanism, but evidence for this is inconclusive. This report details a patient with incessant fascicular tachycardia. The electrophysiological features, in particular the pattern of resetting response, provided strong evidence for reentry as the tachycardia mechanism. Satisfactory long-term arrhythmia control was achieved with flecainide.     

Simultaneous occurrence of type A and type B Wolff-Parkinson-White conduction abnormalities: case report

A 50 year-old woman with recurrent palpitations presented with electrocardiographic changes of simultaneous type A and type B Wolff-Parkinson-White conduction abnormalities suggesting the presence of multiple anomalous pathways.     

改变扫描野对儿童体部CT图像质量的影响

目的探讨扫描野大小与CT图像质量之间关系。方法分别采用25cm×25cm、35cm×35cm、42cm×42cm扫描野对空间分辨率模体和密度分辨率模体进行扫描,测量出各扫描野时空间分辨率和密度分辨率;对20例病人分别采用25cm×25cm和35cm×35cm扫描野进行扫描,并请有多年临床经验的医师,采用双盲法对图像质量进行比较。结果不同的扫描野其图像空间分辨率和密度分辨率不同,25cm×25cm扫描野的图像空间分辨率最高,可以分辨4个直径0.6mm小孔,其密度分辨率也最高,可以分辨5个直径2.5mm小孔;扫描野为25cm×25cm时,临床应用CT扫描的图像明显比35cm×35cm的图像清晰(P<0.05)。结论CT常用的扫描野范围内,当扫描野为25cm×25cm时,其图像的空间分辨率和密度分辨率最佳。