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At least 109 records · Page 6Linked to original sources

Microcomputer based analysis of nystagmus eye movement.

An algorithm to assist in the computation of routine peripheral nystagmus slow phase velocity (SPV) has been implemented on an Apple based data acquisition system. Waveforms stored by the computer may be output to a dot matrix printer to complement conventional strip-chart recorder output. An estimate of SPV is available after each caloric session. Analysis modes range from a summarized output for inclusion in the clinical report to a detailed beat by beat report comprising waveforms, markers and tabulated results. Problematic signals, beyond the scope of the automatic analysis, may be inspected interactively using a software controlled cursor.

Algorithms

Typical results of computer-olfactometry.

After pulsed peripheral olfactory impulses it is possible, under suitable testing conditions, for specific sensory potentials to be read from the surface of the skull and, after repetitions, added up (olfactorially evoked cortical potentials). Typically, there developes a so-called twin-potential containing the equivalents of the electrical activites of the nervus trigeminus and the nervus olfactorius in two peaks of the cortex equivalents. In an objective manner, in other words without intentional or vegetative influence by the test person, it is possible by the weakening or lack of one or the other or both part-potentials to obtain information about the functioning of the olfactory sense. Typical examples will be presented.

Computers, Analog

Modification and application of the computerized automatic audiometer.

Recently, medical information processing systems applying computers have achieved marked advances in parallel with the development of highly accurate automatic measuring instruments. The authors already in 1974 developed and reported a computerized automatic audiometer containing a micro-computer which stored a program for audiometric procedures. Subsequently the authors have developed a compact, multi-purpose audiometric instrument which executes the standard air-bone conduction audiometry, with the exclusion of masking, automatically with a built-in micro-computer. An outline of the instrument is as follows: 1. The instrument is composed of a memory, a control unit, programs for data processing and measurement, a character display for instructing subjects and an audiogram display. It can be operated manually in the same way as a conventional audiometer. 2. Test errors and any abnormally large differences between the responses of the two ears can be detected automatically, and the tests can then be re-executed manually after finishing the automatic procedure for correction of the data. 3. The instrument is provided with output terminals for connection to an external computer or other peripheral equipment. It is designed to be compact and light weight.

Adult

[Computed tomography and nuclear spin tomography in peripheral lymphedema].

The first reported findings on CT and N.M.R. in two cases of idiopathic peripheral lymphoedema are described. These methods have compared with the generally available volume estimations (volume estimation according to Kuhnke, immersion plethysmography) and have been considered in relation to visual and lymphographic examinations.

Adult

Cytokinetic analysis of the impaired proliferative response of peripheral lymphocytes from aged humans to phytohemagglutinin.

The effect of donor age on the rate of cell entry into the proliferating pool and subsequent cell cycle duration for peripheral lymphocytes stimulated by phytohemagglutinin (PHA) were examined by using the bromodeoxyuridine incorporation-differential staining technique. Distribution curves for the appearance of metaphase cells in successive generations as a function of culture time were obtained and analyzed both graphically and by a computer simulation model. Peripheral lymphocytes from aged individuals (approximately 75 yr) were stimulated by PHA at approximately one-half of the rate of peripheral lymphocytes from young individuals (approximately 21 yr). Subsequent cell-cycle durations were estimated to range from 10.0 to 25.0 h for aged individual lymphocyte cultures and 10.6-15.6 h for young individual lymphocyte cultures. The possible significance of these findings to aging in general is discussed.

Adult

Is a higher sampling rate desirable in the computer processing of the pediatric electrocardiogram?

A considerably large number of ECGs of pediatric patients had small notches and slurs on QRS complexes. By sampling these ECGs at higher rates, namely 4 KHz, it was shown that the higher rate data accurately reconstructed the notches and slurs on the QRS complex which were occasionally missed or distorted when the sampling rate was 250 Hz. When using the sampling rate of 250 Hz, it was observed that the reduction of the peak-to-peak amplitude of a QRS complex exceeded 0.1 mV in nearly 30 percent of tested cases, even if the ECG did not contain unwanted noise signals. Moreover, if there is relatively more noise in children's ECGs, one should reduce noise in such data in order to prevent measurement errors in the succeeding steps of the computer program. In such circumstances, the higher sampling rate would be preferable since filtering techniques which are used to reduce noise may considerably affect the estimation of the onset, offset and amplitude of the intrinsic ECG signals if the sampling rate is low. The reduction of the price of computers and their peripheral devices may facilitate the adoption of the higher sampling rate. From these considerations it was concluded that the use of the higher sampling rate might be both practical and an effective measure to enhance the diagnostic performance of the computer ECG systems.

Child

The peripheral zone of increase density in cranial computed tomography.

The band of increased attenuation seen on in vivo CCT images of adults, frequently designated as the cerebral cortex, has been proved clinically and experimentally to be an artifact in the reconstructed image. Recognition of this artifact may be of help in identifying intracranial lesions, such as shallow subdural hematomas. Attenuation values of isolated cortex and white matter were also studied and do not account for the band of high attenuation.

Adult

[Fully automatic computer-analysis of electrocardiograms in clinical routine (author's transl)].

A fully automated Ecg recording and interpretation system (Hewlett Packard HP 5) consisting of a central computer and two peripheral units was evaluated during a four-month period. Ecgs were transmitted via public telephone lines, as was the report from central station to peripheral recording and print-out unit. Within a few seconds after recording and print-out unit. Within a few seconds after recording and transmission a preliminary report is available in printed format. The transmitted Ecgs are stored at the central computer and are being retrieved and evaluated manually there. Three cardiologists read the tracings and furnished final reports. 468 Ecgs were thus compared in our test time of 10 days for statistical evaluation with the following results: 1. 73.1% of all statements were read correctly by the computer. 2. There is a large range of diagnostic accuracy between 0% and 100%. 3. The evaluation of Ecg changed by cardiologists reflects the individual experience of the controllers regarding the Ecg statements as well as computer-dependent possibilities like modification etc. of Ecg. 4. As an example the diagnosis "myocardial infarction" is compared with other Ecg computer programs by means of a quality index calculated from sensitivity and specificity: HP 5 with 158.5 points reaches a similar level as the Pipberger program with 162.6 and the Bonner with 159.5 points. 5. Referring to false negative results this program is acceptable in all diagnostic groups with ca. 8%, except conduction defects with 17.7%. 6. Referring to false positive results the diagnostic groups myocardial infarction/ischemia and conduction defects are not satisfactory with 36.5% and 23.4%. 7. In all the tested system seems to be very useful in routine Ecg interpretation of bigger hospitals.

Cardiology

Initial blood pressure fall on stand up and exercise explained by changes in total peripheral resistance.

To elucidate the underlying mechanisms of the initial fall in blood pressure on standing upright from the supine position, we measured the beat-to-beat changes in intra-arterial pressure in eight healthy male subjects in response to standing. Changes in stroke volume, cardiac output, and total peripheral resistance were computed from the pressure waveform using a pulse contour method. To determine possible mechanisms for the changes observed on standing, similar measures were made on passive tilting and a brief (3-s) bout of cycle exercise. Standing elicited a transient 25% (23-mmHg) fall in mean blood pressure as a result of a 36% fall in total peripheral resistance. Head-up tilt elicited a gradual change in haemodynamic parameters, which reached plateau levels in 20-30 s. Cycling elicited a transient 17% (18-mmHg) fall in blood pressure and a 41% fall in total peripheral resistance. In addition, we measured right atrial and esophageal pressures in two subjects on standing and cycling and found a 10- to 15-mmHg rise in right atrial pressure without a corresponding change in esophageal pressure. This points to the cardiopulmonary reflex as the primary effector of peripheral vasodilation, but we cannot exclude the possibility that 1) local metabolic vasodilation and 2) central command-mediated cholinergic vasodilation contributed to the fall in vascular resistance.

Adult

Comparison of peripheral and portal routes of insulin infusion by a computer-controlled insulin infusion system (artificial endocrine pancreas).

This study was undertaken to determine the different consequences of portal and peripheral routes of insulin administration by the artificial endocrine pancreas. Intraportal glucose was infused (10 mg./min./kg. for 60 minutes) in anesthetized normal and pancreatectomized dogs while blood glucose concentrations were monitored continuously. During computer-controlled insulin administration normal glucose tolerance was restored by both portal and peripheral routes of insulin delivery. There were also no significant differences in (1) glycemic patterns, (2) insulin infusion patterns, (3) peripheral IRI levels, and (4) total insulin requirements between the two routes. It is apparent that the peripheral route, which is more readily accessible than the portal route, may be an appropriate infusion site for an implantable or portable prosthesis for controlling blood glucose concentration.

Animals

[Evaluation of the dose in permanent implants of I-125].

The Anderson's nomograph is currently used in 125I implants planning. For a given treatment volume, this method provides the activity and the seeds number and spacing. In order to obtain indications of the dose delivered in that 125I volume implants, we computed the average peripheral dose (APD), the average tumor dose (ATD) and the "matched peripheral dose" (MPD), for spherical, ellypsoidal and cylindrical volumes. By using the 125I source dosimetric data, we found that both the APD and the ATD are independent of sources randomizing in both position and orientation. Therefore the 125I seeds can be considered as point sources, provided that the dose values are scaled down by a factor which accounts for the spatial distribution anisotrophy. Since the computed parameters are only dependent on the implanted activity, the L. L. Anderson method can be applied even if brachytherapy treatments are associated with external beam radiotherapy ("boost"-therapy).

Brachytherapy

Incorporation of a SMAC analyzer into the data-processing procedures of a computer-assisted laboratory.

This paper describes the incorporation of a SMAC (Technicon) analyzer into data-processing techniques that have been developed on existing computer hardware during several years. The SMAC system is interfaced directly to a small computer, and suitable peripherals produce a manageable form of result tabulation for subsequent reporting, as well as provide quality-control information to the SMAC operators in real time. The design is such as to facilitate the performance analysis of the SMAC system during its initiation period and during normal service operation.

Autoanalysis

Automatic visual field: a software diagnostic procedure.

A recently developed technique for the automatic acquisition of data on visual field losses was tested, with reliable neuro-ophthalmological parameters, on 300 subjects with and without eye disorders. Algorithms for acquisition and processing of the central visual field were implemented on an IBM-AT personal computer with standard peripherals. The contours of scotomata (visual field losses) were best estimated by probabilistic adaptive enhancement of data sampling in those areas with greater visual variability. Image processing tools were specially designed to extract information concerning the size, shape, position and number of scotomata in the visual field. The diagnosis of wider campimetric lesions required parameters such as symmetry or specularity coefficients, obtainable by analysing the visual field of both eyes. Data obtained were correlated to the pathology involved by univariate statistical tools.

Algorithms

Topological analysis of the three-dimensional structure of the human renal glomerulus using a computer-aided reconstruction system.

A quantitative topological analysis of human renal glomerular capillaries reconstructed from serial sections was performed with the aid of a computer system. The peripheral portions of five glomeruli from each of the subcapsular, midcortical, and juxtamedullary zones were reconstructed, each portion corresponding to about one-sixth the diameter of a glomerulus. Statistically, there was no significant difference in the cycle rank (number of independent cycles) of the glomerular capillary network per unit volume of glomerular capillaries or Bowman's capsule among the three renal zones. It was proved that, irrespective of the location of the glomerulus, the glomerular capillary network possessed a larger cycle rank as the volume of the glomerular capillaries or Bowman's capsule increased. This finding strongly suggests that the mean cycle rank per single glomerulus is largest in the juxtamedullary zone.

Capillaries

[Experiences with a cardiorecorder system for continuous 24-hour registration of heart rate].

Studies regarding to the continuous registration of the heart frequency by a transportable instrument, which can store the data of the heart frequency per minute up to 24h, are presented. It is a tape recorder the speed of which is geared down. Thus a normal tape cassette C 60 is sufficient for a registration of the heart frequency during 2 X 24h. The R-wave of the ECG is registered on the first channel of the tape as a biological signal. Moreover every minute an impulse of a clock is recorded on the second channel of the tape. With help of a second instrument the play back procedure for the 24-h-recording can be performed in about 15 min. The signals of both channels of the tape are transformed in digital rectangle impulses by an installed impulse-converter. The serial impulses are counted per minute with help of the time-mark by an interface in a counter. These data are at disposal in BCD-code. They can be passed on the following peripherals: digital printer, computer, pen-recorder and so on. A parallel standardized recording of the physical activity observed by the subject or by an experimenter allows a statistical evaluation and comparison of the physical activity with the corresponding heart frequency data. Some examples of the aread of occupational health, epidemiology and exercise physiology are discussed.

Electrocardiography

Nucleotide sequence of the pldB gene and characteristics of deduced amino acid sequence of lysophospholipase L2 in Escherichia coli.

The nucleotide sequence of the pldB gene of Escherichia coli K-12, which codes for lysophospholipase L2 located in the inner membrane, was determined. The deduced amino acid sequence of lysophospholipase L2 contains 340 amino acid residues, resulting in a protein with a molecular weight of 38,934. It is characterized by a high content of arginine residues (36 out of 340 residues). The amino acid sequence near the NH2-terminus of the protein is composed of a large number of polar or charged amino acid residues, suggesting that this region cannot be a signal peptide. The hydropathy profile of the deduced amino acid sequence of lysophospholipase L2 was studied. Most of the region was rather hydrophilic, and there was no stretch of hydrophobic amino acid region, such as might be predicted to traverse the lipid bilayer. These results are consistent with the experimental observation that lysophospholipase L2 is extracted by salt solution from the membrane fraction, and it may be classified as a peripheral membrane protein. Computer analysis showed that there is no homology in amino acid sequences between lysophospholipase L2 and other extracellular phospholipases, as well as detergent-resistant phospholipase A, which is another membrane-bound phospholipase in E. coli and whose DNA sequence was determined (Homma, H., Kobayashi, T., Chiba, N., Karasawa, K., Mizushima, H., Kudo, I., Inoue, K., Ideka, H., Sekiguchi, M., & Nojima, S. (1984) J. Biochem. 96, 1655-1664). This is the first report of the primary structure of a lysophospholipase.

Amino Acid Sequence