Pulmonary magnetic resonance angiography

In the past few years magnetic resonance angiography (MRA) of the pulmonary vasculature has advanced from a research tool to a clinically relevant imaging modality. Early 2D phase-contrast and time-of-flight (TOF) sequences without the use of contrast agents were time-consuming and limited by considerable imaging and motion artifacts. Since the introduction of MR scanners with stronger gradients (> 20 mT/m) and contrast-enhanced techniques, imaging of the pulmonary vasculature with adequate spatial resolution within a single breathhold is now possible. In the detection of pulmonary embolism in the lobar or segmental arteries, contrast-enhanced MRA is now on the verge of being considered an established modality, possibly competing with conventional pulmonary angiography and contrast-enhanced helical CT. In the future, utilization of phased-array torso coils, the application of navigator pulse sequences, and 3D time-resolved ultrafast MRA will overcome the final limitations of current techniques. Blood-pool MR contrast agents may provide a “one-stop-shopping” approach to the investigation of lower extremity veins and pulmonary arteries in venous thromboembolism.     

World Wide Web and Internet: applications for radiologists

Global exchange of information is one of the major sources of scientific progress in medicine. For management of the rapidly growing body of medical information, computers and their applications have become an indispensable scientific tool. Approximately 36 million computer users are part of a worldwide network called the Internet or “information highway” and have created a new infrastructure to promote rapid and efficient access to medical, and thus also to radiological, information. With the establishment of the World Wide Web (WWW) by a consortium of computer users who used a standardized, nonproprietary syntax termed HyperText Markup Language (HTML) for composing documents, it has become possible to provide interactive multimedia presentations to a wide audience. The extensive use of images in radiology makes education, worldwide consultation (review) and scientific presentation via the Internet a major beneficiary of this technical development. This is possible, since both information (text) as well as medical images can be transported via the Internet. Presently, the Internet offers an extensive database for radiologists. Since many radiologists and physicians have to be considered “Internet novices” and, hence, cannot yet avail themselves of the broad spectrum of the Internet, the aim of this article is to present a general introduction to the WWW/Internet and its applications for radiologists. All Internet sites mentioned in this article can be found at the following Internet address: http://www.univie.ac.at/radio/radio.html (Department of Radiology, University of Vienna) Received: 2 February 1998; Revision received: 11 June 1998; Accepted: 27 July 1998     

The Production and Use of an Attitudinal Film in Birth Control Education

In order to help improve the effectiveness of birth control education programs, a film "It Couldn't Happen to Me" was produced focusing on the psychological motives involved in the non-use of birth control among teenagers. Preliminary evaluation of the film took place with five sample groups: high school students, university students, nursing students, health educators, and Planned Parenthood workers. Survey results indicate that the film is relevant for each of these groups. Pre and posttest measures of the attitudes of the university and nursing samples indicate that the film makes viewers more aware of the psychological factors involved in the non-use of birth control.     

Characterization of the procoagulant chain derived from human high molecular weight kininogen (Fitzgerald factor) by human tissue kallikrein

Human high molecular weight kininogen (HMWK), a single-chain protein with mol wt 120,000, is cleaved by human urinary kallikrein (HUK) to release kinin from within a disulfide loop and form a two-chain protein that retains all the procoagulant activity of the native molecule. Cleavage of HMWK by HUK is associated with a reduction in size to mol wt 115,000, as assessed by SDS-PAGE of unreduced protein, whereas the two chains of the reduced protein present together as a single broad band with mol wt 64,000. The 64,000 chain with procoagulant activity was chromatographically separated from the nonfunctional chain of similar size. The homogeneous procoagulant chain had an amino acid composition similar to that of smaller procoagulant ("light") chains isolated by others upon cleavage of HMWK with plasma kallikrein and elicited an antiserum that was monospecific by Ouchterlony analysis and inhibited the procoagulant function of HMWK. Thus, the limited proteolysis of HMWK by HUK has permitted, for the first time, the isolation of a stable procoagulant chain that is equal in size to the nonfunctional chain. The common terminology of "heavy" and "light" chain for kinin-free kininogen obtained with plasma kallikrein reflects the continued degradation of the procoagulant carboxyterminal chain and is not appropriate for the initial two-chain product formed when kinin is released from HMWK. It is proposed that the initial cleavage products of HMWK be designated the A-chain, the B-fragment, and the C- chain, representing the amino-terminal chain, the released vasoactive peptide containing the bradykinin sequence, and the carboxy-terminal procoagulant chain, respectively. Thus, intact HMWK would contain, in sequence, A, B, and C regions.     

Evaluation of poly(styrene-4-sulfonate) as a preventive agent for conception and sexually transmitted diseases

A commercial preparation of a sodium polystyrene sulfonate (designated as N-PSS; its molecular weight is 500000 daltons) was tested as an inhibitor of sperm function and as a preventive agent for conception and the transmission of sexually transmitted diseases. The polymer is an irreversible inhibitor of hyaluronidase and acrosin; its IC50 values are 5.7 microg/mL and 0.5 microg/mL, for hyaluronidase and acrosin, respectively. N-PSS is also a stimulus of human sperm acrosomal loss. It produces maximal acrosomal loss at 2.5 microg/mL. Contraception in rabbits is nearly complete when rabbit spermatozoa are pretreated with 0.5 mg/mL of N-PSS before artificial insemination; however, N-PSS does not immobilize spermatozoa at concentrations as high as 50 mg/mL. N-PSS has broad spectrum antiviral and antibacterial activities. Infection by human immunodeficiency virus and herpes simplex virus are inhibited by N-PSS; 3-log reductions are produced by 7 microg/mL and 3 microg/mL, respectively. N-PSS is active against Chlamydia trachomatis and Neisseria gonorrhoeae. At 1 mg/mL, N-PSS inhibits chlamydial infectivity by more than 90%. N-PSS produces a 3-log reduction in gonococcal growth at 15 microg/mL. In contrast, N-PSS (5 mg/mL) does not affect the growth of Lactobacillus (normal component of the vaginal flora). N-PSS can be classified as a noncytotoxic contraceptive antimicrobial agent. These properties justify bringing a polystyrene sulfonate into clinical trials for its evaluation as a preventive agent for conception and several sexually transmitted diseases.     

Attacking Key Performance Indicators in Soccer: Current Practice and Perceptions from the Elite to Youth Academy Level

Key Performance Indicators (KPIs) are used to evaluate the offensive success of a soccer team (e.g. penalty box entries) or player (e.g. pass completion rate). However, knowledge transfer from research to applied practice is understudied. The current study queried practitioners (n = 145, mean ± SD age: 36 ± 9 years) from 42 countries across different roles and levels of competition (National Team Federation to Youth Academy levels) on various forms of data collection, including an explicit assessment of twelve attacking KPIs. 64.3% of practitioners use data tools and applications weekly (predominately) to gather KPIs during matches. 83% of practitioners use event data compared to only 52% of practitioners using positional data, with a preference for shooting related KPIs. Differences in the use and value of metrics derived from positional tracking data (including Ball Possession Metrics) were evident between job role and level of competition. These findings demonstrate that practitioners implement KPIs and gather tactical information in a variety of ways with a preference for simpler metrics related to shots. The low perceived value of newer KPIs afforded by positional data could be explained by low buy-in, a lack of education across practitioners, or insufficient translation of findings by experts towards practice.Key points

• Soccer practitioners collect data and evaluate performance in a variety of ways depending on the level of competition and their role within a club or federation.
• Practitioners reported a preference for shooting related metrics gathered by event data compared to KPIs offered by optical positional tracking technology.
• Despite increased interest and the capability to measure contextual aspects of passing performance with tracking technology, most practitioners still rely on more easily computed metrics (e.g. Pass Completion Percentage) and ball possession KPIs (e.g. Total Duration of Possession).
• This study highlights a gap in knowledge transfer between research and practice, encouraging increased education and collaborative efforts between data/sport scientists and practitioners to progress the field of analytics towards practical use in soccer.

Key words: Football, soccer, match analysis, performance analysis, applied data-science