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At least 145 records · Page 8Linked to original sources

Confocal fluorescence microscopy and three-dimensional reconstruction.

Several recent technological advances have considerably improved the field of confocal fluorescence microscopy. Improvements in confocal microscope design, new fluorescent probes and indicators, more sensitive imaging devices, and computer advances which allow for data manipulation and storage provide a convenient method to acquire complex three-dimensional (3-D) architectural details which previously were difficult or impossible to obtain from biological specimens. Applications of the laser scanning and tandem scanning confocal microscopes offer the potential for gaining powerful insights into the complex relationship of cellular structure and function. Confocal microscopy generates optical sections free from out-of-focus blur. With the development of new visualization tools to render and display complex 3-D data, a set of optical sections taken at different focal planes can be three-dimensionally reconstructed to create an animated sequence which can reveal latent features of the specimen. The combination of confocal microscopy and 3-D reconstruction provides a powerful new imaging tool to advance knowledge about structural and functional cellular properties as they occur dynamically in three dimensions.

Animals↗

Direct measurement of sarcomere length from isolated cardiac cells.

Isolated cardiac muscle cells enzymatically digested with collagenase and hyaluronidase from whole rat myocardium demonstrate the characteristics of an intact membrane in that they tolerate millimolar concentrations of free Ca2+ and exhibit phasic contractions with electrical excitation. These isolated cells maintain their characteristic A-I band striation patterns when at rest or during contraction. An apparatus has been developed to directly image these cells with phase-contrast micrography onto a 1,728-element charge-coupled device photodiode array for rapid data storage in a digital computer. The digitized striation pattern profile was analyzed for individual and average sarcomere spacing. In isotonic media the average resting sarcomere length ranged from 1.77 to 1.91 micrometers in 13 cells, with a mean length of 1.83 +/- 0.12 micrometers. Electrically stimulated phasic contractions in three cells demonstrated a synchronous 20% decrease in sarcomere spacing to a mean of 1.51 micrometers. Striation spacing decreased under hypertonic stress but elongated only up to 1.93 micrometers in hypotonic solutions, suggesting that some internal elastic constraint exists that limits elongation of the cell.

Animals↗

Digital archive center: implementation for a radiology department.

OBJECTIVE: In this article, we describe the implementation of a digital archive center for a radiology department in a 700-bed teaching hospital. MATERIALS AND METHODS: The archive center consists of two identical archive systems, each comprising five components: an archive server, a data-base server, an optical disk library, a stand-alone optical disk drive, and a communication network. An image management system controls the image traffic from acquisition devices to display stations. A fault-tolerant mechanism was built into the archive center to achieve a 100% uptime. RESULTS: The center has been in operation for over 6 months. We have not experienced a single total system failure during this period. It currently archives all digital images from three MR units and four CT scanners and selected images from three computed radiographic systems and two laser film digitizers. The center archives between 1.5 and 2.0 gigabytes of images per workday. CONCLUSION: With its built-in fault-tolerant mechanism, we believe that the implemented archive center is very reliable and is suitable for a radiology department to archive its digital images.

Hospital Bed Capacity, 500 and over↗

Validation of two devices for self-measurement of blood pressure by elderly patients according to the revised British Hypertension Society protocol: the Omron HEM-722C and HEM-735C.

BACKGROUND: The validation of self-measurement devices for clinical use by elderly patients has been recommended. The Omron HEM-722C device has recently been validated according to the British Hypertension Society (BHS) protocol for use for general populations and the Omron HEM-735C is a new fully automatic device with a high capacity for storage of measurements that is integrated with a personal computer. OBJECTIVE: To perform a clinical validation for use by elderly people of the Omron HEM-722C and HEM-735C devices according to the revised protocol of the BHS and the criteria of the Association for the Advancement of Medical Instrumentation (AAMI). METHODS: We carried out a main validation test according to the revised BHS protocol for validation procedures for special groups on two groups of 30 subjects aged more than 65 years (29 men and 31 women), 11 of 30 with systolic blood pressures (SBP) <110mmHg, 10 of 30 with SBP >200 mmHg, 15 of 30 with diastolic blood pressures (DBP( <70 mmHg and 10 of 30 with DBP >110 mmHg. The results were graded according to the BHS system from A to D. RESULTS: The Omron HEM 722C achieved an overall A/A grading and satisfied the AAMI criteria for accuracy whereas the Omron HEM-735C achieved an overall B/A grading and satisfied the AAMI criteria for accuracy. The sphygmomanometer measurements were 147 +/- 31/79 +/- 15 and 144 +/- 30/78 +/- 15 mmHg (means+/-SD) respectively, for the models 722C and 735C. The average differences between mercury sphygmomanometer and HEM-722C readings for SBP and DBP were, respectively, 0.76+/-5 and 0.41+/-8 mmHg; those for HEM-735C were, respectively, 0.24+/-8 and 0.9+/-8 mmHg. Readings of the HEM-722C device differed by less than 5 mmHg for 76% of systolic readings and 96% of the readings differed by less than 10 mmHg. Diastolic measurements differed by less than 5 mmHg for 71% and less than 10 mmHg for 71 and 87% of all readings. Readings of the HEM-735C device differed by less than 5 mmHg for 68% of systolic readings and 74% of the readings differed by less than 10 mmHg. Diastolic measurements differed by less than 5 mmHg in 74% and less than 10 mmHg in 88 and 87% of all readings. CONCLUSIONS: On the basis of these results, for elderly subjects both self-measurement devices (Omron HEM-722C and HEM-735C) satisfied the validation criteria of the BHS and therefore can be recommended for the clinical measurement of blood pressure in elderly patients.

Automation↗

A hardware device for recognition of P and QRS waves.

A new hardware device has been constructed to detect QRS and P complexes for the purpose of automatic arrhythmia interpretation. This apparatus can operate in noisy conditions and provide synchronized pulses representative of P complex, QRS complex, wide QRS, and premature QRS to different output channels. P wave identification is achieved with a high degree of reliability through a specially designed bipolar electrode catheter. The device could minimize demands on central processor time and core storage computer.

Arrhythmias, Cardiac↗

CARDIOMEDIA: a communicable multimedia medical record on Intranet and digital optical memory card.

As part of French health reform, French physicians were computerised by the end of 1998. A specific Intranet network will be used to communicate medical data between the health professionals. The objectives of the CARDIOMEDIA project were to develop and evaluate the feasibility of a coronary multimedia data record stored on an optical card and communicable on Intranet within the hospital. Patients treated by angioplasty at the University Hospital of Rennes participated in the experiment. In general, patients are treated in the University Hospital and are followed up by another health care provider closer to their home. The patient leaves the University Hospital with his card, which is directly available elsewhere for emergency or for consultation. This approach is assumed to reduce the number of examinations and to offer a better patient follow-up. The CARDIOMEDIA card is a specialised record including various data types: text, images, image sequences of coronarography and ECG signals. For this purpose an optical card with its large memory is very convenient. We used the DICOM format for image exchange and management. It is combined with CARDIOMEDIA specific compressing software. For the multimedia record the HTML format and web Intranet method are chosen. This provides an intuitive interface which can combine various data types and helper applications like a DICOM image viewer.

Angioplasty↗

Computer-aided communication device for a child with cerebral palsy.

This paper describes a portable computer-aided communication device designed for a 13-year-old child with athetoid cerebral palsy. The device was intended to provide vocal output, hard-copy, correctable display, word storage capabilities, and utilize currently available technology. The design incorporated the Epson HX-20 computer, the Votrax Type 'N Talk speech synthesizer, and a customized laptray.

Adolescent↗

A critical investigation of the measurement of the force required to dilate the human uterine cervix.

A system for objectively analysing the forces of dilation of the human uterine cervix was devised using a force sensing device linked to a BBC microcomputer. The computer program allowed easy recording, storage and analysis of force/time curves obtained from the passage of tapered dilators through the cervix. A new design of dilator gave a smoother force/time curve. These force/time curves were analysed. Six indices: peak force, end force, area to peak, area to end the ratio of the peak and end forces recorded from the passage of the two largest and two smallest dilators, were compared. Area measurement was subject to artefact and rejected. Peak and end force measurements gave the best separation between parous and nulliparous patients. The peak force was judged to be the better as it was found to be easier to define than end force.

Biophysical Phenomena↗

Drawing two conclusions on pen computers.

In a modern version of David and Goliath, backers of hand-held pen computers hope to make serious inroads against well-established computer workstations. A start-up company, Practice Technology Inc., wants to build information networks based on pen computing. But it's going up against well-established network vendors that are relying on PC-based systems. Meanwhile, two pen computer manufacturers have stopped producing those devices, citing lack of demand.

Industry↗

IS & C system and file protection mechanism.

This paper reports a new extension of IS & C (Image Save And Carry) project. Because IS & C is an off-line system and requires full compatibility so as to enable medical data interchange with ease among hospitals and clinics, specifications that are indispensable for compatibility have been standardized by the IS & C committee. The IS & C system is supposed to be used in medicine, so the file protection mechanism for the security of the recorded files has been also developed. The characteristics of IS & C volume and file structure and the second national project being carried out in National Cancer Center Hospital are briefly explained as well.

Computer Communication Networks↗

An introduction to fractal imaging technology.

In this article the author explains the basic theory and practical applications of the latest advancement in imaging technology called fractal imaging. Fractal imaging is a unique way of compressing and storing images which has unlocked the door to the restrictions imposed by conventional imaging technology as regards storage and transmission of high quality images. The article outlines how this technology has been successfully applied by the creation of the first and only fractal photographic archival and retrieval system in Scotland, in the form of the George Washington Wilson collection comprising 44,000 images and associated text in only 450 megabytes (Mb) of disc space.

Fractals↗

Uses and limitations of microcomputers for epidemiological research in occupational health.

The rapid improvements in microcomputer systems have contributed to ease of performance of epidemiological research in occupational health. Computers now available can aid in all stages of research- from the early stages of literature review to data collection, analysis and presentation. Optical storage devices now allow large occupational health data bases to be stored on a single compact disc, with the information accessible by microcomputer. Hand-held computers and optical scanners allow paperless collection of field data. Epidemiological analysis and data presentation is easily done with software packages, some of which are in the public domain. However, there are limitations in the use of computers for any epidemiological research. Investment of time is required to learn the use of a computer. Care needs to be taken to ensure accurate data entry, and correct choice has to be made of methods for subsequent statistical analysis. Microcomputers are valuable as labour saving devices, but cannot replace proper planning, execution and appropriate data analysis in epidemiological research in occupational health.

Health Services Research↗

Present status and performance of PACS at Kyoto University Hospital.

A pilot PACS project, named KIDS, has been running in Kyoto University Hospital. The purpose of the system is to establish a small PACS that includes all digital imaging modalities and to evaluate it. The project has been continued from the first phase (KIDS-1) to the second phase (KIDS-2). In the first phase, a small-scale PACS was developed. In the second phase, the expansion of coverage of modalities and completion of the image database was intended. At present, the database contains image data of 16264 patients amounting to 150 Gbytes. Simulation of the retrieval process to the database shows that 154.3 s per patient is required for retrieving his/her entire image data. This calculated value is close to the actual time.

Computer Communication Networks↗

Computer-monitored radionuclide tracking of three-dimensional mandibular movements. Part I: theoretical approach.

A new technique for the three-dimensional recording of a person's mandibular movement is described. A small and harmless radioactive source is fixed on the patient's skin at the point of interest or sealed in a tooth cavity. Using the proper collimation, the motion of the point source is recorded via a gamma camera and minicomputer. Long-term storage on a magnetic device offers playback, slow motion facilities, and data analysis through the use of sophisticated computer languages. Simultaneous recordings using two cameras, or postsynchronization of two different views of an experiment, enable the three-dimensional restitution of mandibular movements. Superimposition of a grid of radioactive spots spaced at measured intervals during the recording permits a straightforward calibration of the patient's motion. Multiple sources in a single experiment may be recorded to describe the displacement of several points of interest. This method, derived from nuclear medicine techniques, offers a powerful tool of general interest for the tracking of dynamic events in many fields of dentistry such as temporomandibular joint dysfunction and prosthetic restorative techniques. Further considerations on our experimental settings and results will be published in part II.

Analog-Digital Conversion↗