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At least 433 records · Page 24Linked to original sources

Telemedicine in ultrasound: new solutions.

The transport of dynamic ultrasound (US) pictures as video files or streams no longer presents a problem. Despite teleconferencing, this method of transfer provides no active influence on the data sent for the receiving expert. We are evaluating a software-based 3-D US system that provides the new opportunity of an active US re-evaluation of a virtual patient. The 3-D volumes can be reanalyzed, time- and examiner-independent, wherever the device is installed. To test the clinical feasibility of this virtual US investigation, we installed the device in a peripheral hospital and in our US unit. The transfer of the volume (about 10 to 15 MB) could be done with two parallel Integrated Services Digital Network (ISDN) lines with a conduction capacity of 128 KB/s. In this basic assessment, the transmission of US volumes of patients proved to be easy in the acquisition, quick in off-line transmission and reliable in off-line re-evaluation of the data.

Computer Communication Networks↗

Design of a radiation surveillance unit for an unmanned aerial vehicle.

This paper describes a prototype of a compact environmental radiation surveillance instrument designed for a Ranger unmanned aerial vehicle. The instrument, which can be used for tracking a radioactive plume, mapping fallout and searching for point sources, consists of three different detector types (GM, NaI(Tl) and CZT) and an air sampling unit. In addition to the standard electronics for data acquisition, the system contains an onboard computer, a GPS receiver and environmental sensors, all enclosed in a single housing manufactured of fiberglass-reinforced composite material. The data collected during the flight is transmitted in real-time to the ground station via a TETRA radio network. The radiation surveillance unit is an independent module and as such can be used in, for example, airplanes, helicopters and cars.

Accidents, Aviation↗

The effects of delayed physical prompts and reinforcement on infant sign language acquisition.

Researchers and clinicians have recommended that sign language be taught to typically developing children during their first 2 years of life; however, existing research does not provide adequate information regarding appropriate methods of sign training. We used delayed physical prompting and reinforcement to teach manual signs to 3 children between the ages of 6 and 13 months. Data were collected on the occurrence of prompted and independent signs as well as crying. Sign training was successful in producing independent signing in all 3 children in under 4 hr of training per child.

Communication↗

Internet-based data inclusion in a population-based European collaborative follow-up study of inflammatory bowel disease patients: description of methods used and analysis of factors influencing response rates.

AIM: To describe an Internet-based data acquisition facility for a European 10-year clinical follow-up study project of a population-based cohort of inflammatory bowel disease (IBD) patients and to investigate the influence of demographic and disease related patient characteristics on response rates. METHODS: Thirteen years ago, the European Collaborative study group of IBD (EC-IBD) initiated a population-based prospective inception cohort of 2 201 uniformly diagnosed IBD patients within 20 well-described geographical areas in 11 European countries and Israel. For the 10-year follow-up of this cohort, an electronic patient questionnaire (ePQ) and electronic physician per patient follow-up form (ePpPFU) were designed as two separate data collecting instruments and made available through an Internet-based website. Independent demographic and clinical determinants of ePQ participation were analyzed using multivariate logistic regression. RESULTS: In 958 (316 CD and 642 UC) out of a total number of 1 505 (64%) available IBD patients, originating from 13 participating centers from nine different countries, both ePQ and ePpPFU were completed. Patients older than 40 years at ePQ completion (OR: 1.53 (95%CI: 1.14-2.05)) and those with active disease during the 3 mo previous to ePQ completion (OR: 3.32 (95%CI: 1.57-7.03)) were significantly more likely to respond. CONCLUSION: An Internet-based data acquisition tool appeared successful in sustaining a unique Western-European and Israelian multi-center 10-year clinical follow-up study project in patients afflicted with IBD.

Adult↗

Multidimensional dipolar exchange-assisted recoupling measurements in solid-state NMR.

Aseries of uni- and multidimensional variants of the dipolar exchange-assisted recoupling (DEAR) NMR experiment is described and applied to determinations of (13)C-(14)N dipolar local field spectra in amino acids and dipeptides. The DEAR protocol recouples nearby nuclei by relying on differences in their relative rates of longitudinal relaxation, and has the potential to give quantitative geometric results without requiring radiofrequency pulsing on both members of a coupled spin pair. One- and two-dimensional variants of this recoupling strategy on generic I-S pairs are discussed, and measurements of (13)C-(14)N distances and 2D local field experiments sensitive to the relative orientation of CN vectors with respect to the (13)C shielding tensor are presented. Since these measurements did not involve pulsing on the broad nitrogen resonance, their results were independent of the quadrupolar parameters of this nucleus. High-resolution 3D NMR versions of the 2D experiments were also implemented in order to separate their resulting local field patterns according to the isotropic shifts of inequivalent (13)C sites. These high-resolution 3D acquisitions involved collecting a series of 2D DEAR NMR data sets on rotating samples as a function of spinning angle, and then subjecting the resulting data to a processing akin to that involved in variable-angle correlation NMR. Once successfully tested on l-alanine this experiment was applied to the analysis of a series of dipeptides, allowing us to extract separate local field (13)C-(14)N spectra from this type of multisite systems.

Amino Acids↗

An integrated approach to scanning microscope data acquisition.

This paper describes an integrated data acquisition system built for a cryogenic STEM which is currently under construction in the authors' laboratory. Advantage was taken of modern digital and microprocessor techniques to construct a versatile and expandable system in the minimum time. The system is able to operate in conjunction with an external image processing computer or as an independent system with built-in image processing facilities.

Computers↗

Vaccinia virus encodes four putative DNA and/or RNA helicases distantly related to each other.

Computer-assisted analysis of the amino acid sequences of vaccinia virus proteins containing the purine NTP-binding pattern revealed the seven motifs typical of the DNA (RNA) helicase superfamily II in the proteins I8R and A18R. Together with the previously described putative helicases D6R and D11L, the number of putative helicases of this superfamily encoded by the genome of vaccinia virus now reaches four. Aside from the helicase motifs, the sequences of I8R and A18R showed no strong similarity to each other, nor to D6R and D11L. Statistically significant similarity was demonstrated between I8R and the putative RNA helicases involved in pre-mRNA splicing in yeast, PRP2, PRP16 and PRP22, whereas A18R appeared to be related to the putative helicases encoded by the human DNA repair gene ERCC3 and the D10 gene of bacteriophage T5. These findings suggest that I8R may be an RNA helicase. Based on the known properties of the virion NTPases of vaccinia virus, it is possible that the I8R protein may be identical to the previously characterized virion NTPase II. A18R is likely to possess DNA and/or RNA helicase activity. Circumstantial evidence suggests that this activity might be involved in melting duplex structures in late mRNAs. The possibility of independent acquisition of the putative helicases I8R, A18R and a common progenitor to D6R and D11L by an ancestral poxvirus is discussed.

Amino Acid Sequence↗

Phylogenetic relationships and taxonomic position of Chlorella-like isolates from low pH environments (pH < 3.0).

BACKGROUND: Little is known about phytoplankton communities inhabiting low pH environments such as volcanic and geothermal sites or acidic waters. Only specialised organisms are able to tolerate such extreme conditions. There is, thus, low species diversity. We have characterised the previously isolated acid tolerant Chlorella-like microalgae Viridiella fridericiana and Chlorella protothecoides var. acidicola by microscopical and biomolecular methods in order to assess their phylogenetic relationships. RESULTS: Both isolates belong to the trebouxiophycean lineage of chlorophytes. 18S and ITS1 sequence data clearly confirm that Viridiella fridericiana constitutes a new genus apart from the morphologically similar and likewise acid tolerant microalga Chlorella saccharophila. Chlorella protothecoides var. acidicola on the other hand is not a variety of Chlorella protothecoides but falls within a heterogeneous cluster consisting of Nannochloris, "Chlorella" spec. Yanaqocha, and Koliella, and is most closely related to algae which were also isolated from extreme environments. CONCLUSIONS: The distribution of acid tolerant strains in the 18S rRNA tree shows that acquisition of acid tolerance was unlikely a monophyletic event in green microalgae. We propose that different strains have independently adapted to extreme environments. Some of them have spread worldwide and were able to colonise other extreme habitats. Considering the problems of successfully isolating acid tolerant strains, acidic soils could represent an unsuspected source of biological diversity with high potential for biotechnological utilisations.

Adaptation, Physiological↗

Three-dimensional cerebral contrast-enhanced magnetic resonance venography at 3.0 Tesla: initial results using highly accelerated parallel acquisition.

OBJECTIVE: The objective of this study was to evaluate a high spatial resolution 3-dimensional (3D) contrast-enhanced magnetic resonance (CE-MR) venography protocol for evaluation of intracranial venous system using highly accelerated parallel imaging at 3.0 T. MATERIALS AND METHODS: Ten patients (4 male, 6 female; age, 38-76 years) with suspected cerebrovascular disease were prospectively studied on a 32-channel 3.0 T MR system. After a single intravenous contrast injection, high spatial resolution 3D CE-MR angiography of the entire supraaortic arteries was performed followed immediately by 3D cerebral CE-MR venography. By using a fast 3D gradient-recalled-echo sequence with elliptic centric k-space ordering and highly accelerated parallel acquisition (acceleration factor 3 and 2 in phase and slice encoding direction, respectively), 3D cerebral CE-MR venography was acquired with voxel dimensions of 0.7 x 0.7 x 0.8 mm in 24 seconds. Image evaluation was performed independently by 2 neuroradiologists for overall image quality, presence of noise, and artifacts. The image quality of 30 venous segments was evaluated in each subject using a 1 to 4 scoring scale. In 2 patients, catheter angiography was available for correlation. Statistical analysis of data was performed by using Wilcoxon rank sum test and kappa coefficient. RESULTS: All studies were determined to be of diagnostic image quality by both observers. The majority (90%) of cerebral venous segments were evaluated to be of diagnostic image quality (median, 3; range, 3-4) by both readers and with excellent interobserver agreement (kappa = 0.86; 95% confidence interval, 0.79-0.93). One meningioma invading the superior sagittal sinus and one superior sagittal sinus fistula were detected subsequently confirmed by conventional angiography. CONCLUSION: High spatial resolution 3D cerebral CE-MR venography is feasible and promising. Using a 32-channel 3.0 T system combined with multichannel array coils effectively supports highly accelerated parallel imaging, enabling subsequent acquisition of both high spatial resolution CE-MR angiography and CE-MR venography after a single contrast injection without impairing the image quality. More extensive clinical studies are warranted to establish the range of applications and confirm the accuracy of this technique.

Adult↗

Design and operation of a nuclear medicine picture archiving and communication system.

Construction of a new Veterans Administration Medical Center provided a unique opportunity to design and implement a state-of-the-art nuclear medicine department in a large teaching and research hospital. The new medical center allowed the acquisition of all new gamma cameras and computer systems without any historical need to patch together a system of old and new equipment. The picture archiving and communication system (PACS) was designed to link five gamma cameras to four image viewing areas, followed by digital archive on an optical disc. The gamma cameras' computers and viewing areas' computers are linked to a central networking computer in a manner that provides nine independent but digitally communicating image computers. Each nuclear medicine computer is capable of acquiring gamma camera data while possibly also performing up to three other simultaneous tasks: analysis of image data, transfer of image data from node to node, and patient database manipulation. The nine image computers each appear to the user as a digital file cabinet, containing various folders, which in turn contain patient studies. To transfer a patient study from one location to another, the user simply queues a transfer request by selecting a file drawer-folder combination for the source and destination locations. It takes only a few seconds to queue a transfer request, and the transfer is complete about a minute later without any further user intervention. A computer genie awakens during the early morning off-hours and performs housekeeping tasks, including movement of patient studies (based on date of acquisition) from active viewing folders to inactive archive folders. All scheduling, workload data, patient image reports, etc, are handled by a patient textual information database system. Patient reports and scheduling information are transmitted to the medical center's central computer where they are made readily available throughout the medical center. The PACS, in clinical use since the spring of 1988, is practical and well-received by technologists, nuclear medicine physicians, and more importantly, our consumer, the referring physicians.

Hospital Information Systems↗

Prevalence of and risk factors for colonization with methicillin-resistant Staphylococcus aureus at the time of hospital admission.

OBJECTIVES: To determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonization among patients presenting for hospital admission and to identify risk factors for MRSA colonization. DESIGN: Surveillance cultures were performed at the time of hospital admission to identify patients colonized with S. aureus. A case-control study was performed to identify risk factors for MRSA colonization. SETTING: A tertiary-care academic medical center. PATIENTS: Adults presenting for hospital admission (N = 974). RESULTS: S. aureus was isolated from 205 (21%) of the patients for whom cultures were performed. Methicillin-sensitive S. aureus was isolated from 179 (18.4%) of the patients, and MRSA was isolated from 26 (2.7%) of the patients. All 26 MRSA-colonized patients had been admitted to a healthcare facility in the preceding year, had at least one chronic illness, or both. In multivariate analyses comparing MRSA-colonized patients with control-patients, admission to a nursing home (odds ratio [OR], 16.5; 95% confidence interval [CI95], 1.4 to 192.1; P = .025) or a hospitalization of 5 days or longer during the preceding year (OR, 3.91; CI95, 1.1 to 13.9; P = .035) were independent predictors of MRSA colonization. CONCLUSIONS: Patients colonized with MRSA admitted to this hospital likely acquired the organism during previous encounters with healthcare facilities. There was no evidence that MRSA colonization occurs commonly among low-risk individuals in this community. These data suggest that evaluation of recent healthcare exposures is essential if true community acquisition of MRSA is to be confirmed.

Academic Medical Centers↗

Mk3.5: a modular, multi-frequency successor to the Mk3a EIS/EIT system.

This paper describes the Sheffield Mk3.5 EIT/EIS system which measures both the real and imaginary part of impedance at 30 frequencies between 2 kHz and 1.6 MHz. The system uses eight electrodes with an adjacent drive/receive electrode data acquisition protocol. The system is modular, containing eight identical data acquisition boards, which contain DSPs to generate the drive frequencies and to perform the FFT used for demodulation. The current drive is in three sequentially applied packets, where each packet contains ten summed sine waves. The data acquisition system is interfaced to a host PC through an optically isolated high speed serial link (RS485) running at 2 Mbaud (2 Mbits s(-1)). Measurements on a saline filled tank show that the average signal to noise performance of the system is 40 dB measured across all frequencies and that this figure is independent of frequency of measurement. These results suggest that the current system is 10 dB better in absolute terms than the previous Sheffield (Mk3a) system.

Electric Impedance↗

Health "Smart" home: information technology for patients at home.

This article reviews the emerging concept of health "Smart" homes (HSH) and its potential through the use of telemedical information systems and communication technologies. HSH systems provide health care services for people with special needs who wish to remain independent and living in their own home. The large diversity of needs in a home-based patient population requires complex technology. Meeting these needs technically requires the use of a distributed approach and the combination of many hardware and software techniques. We also describe the wide scope of new information, communication, and data-acquisition technologies used in home health care. We offer an introduction to the HSH concept in terms of technical, economic, and human requirements. Examples of HSH projects are presented, including a short description of our own smart home and telehealthcare information system project.

Aged↗

Case-control study of Stenotrophomonas maltophilia acquisition in cystic fibrosis patients.

The aims of this case-control study were to describe the characteristics of cystic fibrosis (CF) patients who isolated Stenotrophomonas maltophilia in sputum, to determine risk factors for acquisition, to assess persistence of the organism and clinical outcomes postacquisition. Data were collected from 1991-1999. CF patients and controls (who had never isolated S. maltophilia) were matched for age (+/- 1 yr), sex and forced expiratory volume in one second (+/- 10%). Data were collected from the year prior and for 2 yrs postacquisition of S. maltophilia. The prevalence of S. maltophilia increased from 3.3% to 15%. Factors associated with S. maltophilia acquisition were more than two courses of intravenous antibiotics, isolation of Aspergillus fumigatus in sputum and oral steroid use. The effect of A. fumigatus was independent of steroid use. Clinical status did not change postacquisition. The majority of patients cleared the organism from the sputum. Long-term infection or an accelerated deterioration in lung function or nutrition is not likely post-Stenotrophomonas maltophilia acquisition in cystic fibrosis. This is the first documentation of an association between Aspergillus fumigatus isolation and Stenotrophomonas maltophilia acquisition in cystic fibrosis, independently of steroid therapy.

Adult↗

Word decoding and picture naming in children with a reading disability.

Poor readers and reading age level matched controls performed a primed picture-naming task and a lexical decision task; their vocabulary performance was also assessed. Picture-naming data showed that poor readers were slower in the repeated prime condition only. This effect could not be explained by differences in vocabulary. Semantically related primes were ineffective compared with the repeated prime condition. Lexical decision data replicated the nonword reading deficit hypothesis: Poor readers were slower, particularly on the pseudowords and nonwords. A separately conducted analysis of the real word data showed strong effects of acquisition age. Late-acquired words had longer reaction times. Vocabulary performance as the covariate could explain the between-groups effects on this task. Semantic processing, as it is involved in picture naming, and phonological processing, as it is involved in decoding printed words, appear to be 2 relatively independent sources of reading deficits.

Adolescent↗

The association between genital ulcer disease and acquisition of HIV infection in homosexual men.

We analyzed the association of herpes simplex virus (HSV) infection and syphilis, the two most common causes of genital ulceration in homosexual men, with human immunodeficiency virus (HIV) infection in 200 men enrolled between 1983 and 1986 into a study evaluating the microbial causes of acute proctitis. Infection with HIV was independently associated with a history of syphilis, serologic evidence of syphilis, a history of HSV infection, and antibody to HSV-2. Antibody to HIV was not associated with a history of other genital infections or with antibody to Chlamydia trachomatis or HSV-1. Similar associations were observed in 111 asymptomatic homosexuals seen for HIV screening. Men who presented with primary HSV proctitis had a lower prevalence of HIV antibody than those with preexisting HSV-2 antibody (44% vs 68%); this suggests that HSV-2 infection antedated HIV infection. These data suggest that genital ulcerative diseases are an important risk factor for the acquisition of HIV infection in homosexual men; measures directed at control of these diseases may reduce the transmission of HIV in this population.

Adult↗

Quantitative 1H-magnetic resonance spectroscopy of human brain: Influence of composition and parameterization of the basis set in linear combination model-fitting.

Localized short-echo-time (1)H-MR spectra of human brain contain contributions of many low-molecular-weight metabolites and baseline contributions of macromolecules. Two approaches to model such spectra are compared and the data acquisition sequence, optimized for reproducibility, is presented. Modeling relies on prior knowledge constraints and linear combination of metabolite spectra. Investigated was what can be gained by basis parameterization, i.e., description of basis spectra as sums of parametric lineshapes. Effects of basis composition and addition of experimentally measured macromolecular baselines were investigated also. Both fitting methods yielded quantitatively similar values, model deviations, error estimates, and reproducibility in the evaluation of 64 spectra of human gray and white matter from 40 subjects. Major advantages of parameterized basis functions are the possibilities to evaluate fitting parameters separately, to treat subgroup spectra as independent moieties, and to incorporate deviations from straightforward metabolite models. It was found that most of the 22 basis metabolites used may provide meaningful data when comparing patient cohorts. In individual spectra, sums of closely related metabolites are often more meaningful. Inclusion of a macromolecular basis component leads to relatively small, but significantly different tissue content for most metabolites. It provides a means to quantitate baseline contributions that may contain crucial clinical information.

Adolescent↗

RESUME: a temporal-abstraction system for patient monitoring.

RESUME is a system that performs temporal abstraction of time-stamped data. The temporal-abstraction task is crucial for planning treatment, for executing treatment plans, for identifying clinical problems, and for revising treatment plans. The RESUME system is based on a model of three basic temporal-abstraction mechanisms: point temporal abstraction, a mechanism for abstracting the values of several parameters into a value of another parameter; temporal inference, a mechanism for inferring sound logical conclusions over a single interval or two meeting intervals; and temporal interpolation, a mechanism for bridging nonmeeting temporal intervals. Making explicit the knowledge required for temporal abstraction supports the acquisition and the sharing of that knowledge. We have implemented the RESUME system using the CLIPS knowledge-representation shell. The RESUME system emphasizes the need for explicit representation of temporal-abstraction knowledge, and the advantages of modular, task-specific but domain-independent architectures for building medical knowledge-based systems.

Abstracting and Indexing↗