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PubMed1981

[An automatic non-invasive method for the measurement of systolic, diastolic and mean blood pressure].

A new automatic apparatus for the measurement of arterial pressure by a non-invasive technique was compared with direct intra-arterial measurement in 20 adult patients in a surgical intensive care unit. The apparatus works on the basis of the principle of oscillometry. Blood pressure is determined with a microprocessor by analysis of the amplitude of the oscillations produced by a cuff which is inflated then deflated automatically. Thus mean arterial pressure corresponds to the maximum amplitude. Systolic and diastolic pressures are deduced by extrapolation to zero of the amplitudes on either side of the maximum reading. Mean arterial pressure (AP) proved to be very reliable within the limits studied: 8.0 - 14.7 kPa (60 - 110 mmHg) with a difference in mean direct AP and indirect AP of 0,09 +/- 0.9 kPa SD (0.71 +/- 7 mmHg) and a coefficient of linear correlation between the two methods of r = 0.82. This non-invasive technique determined systolic arterial pressure (sAP) in a less reliable fashion than AP when compared with the invasive technique, with a tendency to flatten the extreme values. The correlation coefficient here was 0.68. Finally, diastolic arterial pressure (dAP) showed a better degree of agreement through with a difference in mean indirect AP and mean direct AP of 1.0 +/- 0.8 kPa (7.6 +/- 6.0 mmHg). These results indicate a good degree of agreement for measurements of mean arterial pressure, clinically the most important, between the two methods used. Measurements of diastolic pressure and above all of diastolic pressure seemed to be less in agreement. This difference could be due to an error in determination of the automatic apparatus tested or to the peripheral site (radial artery) of the intra-arterial catheter used, itself falsifying the humeral arterial pressure.

Blood Pressure Determination↗
PubMed1982

Effect of different beta-blocking agents on an in vitro model of ventricular automaticity.

The effect of 7 beta-blocking agents with different properties such as quinidine like activity (QLA) or intrinsic sympathomimetic activity (ISA) was tested on a model of automaticity induced in the isolated right ventricle of the rat. The following results were obtained: a) Propranolol was the most effective drug for the inhibition of the automatic activity; b) Pronethalol, pindolol and labetalol also decreased the automatic rate. Acebutolol was less effective than these three drugs but with larger concentrations also decreased the preparation's frequency; c) Neither sotalol nor practolol decreased the preparation's frequency, but practolol increased that frequency at higher concentrations. We conclude that QLA might play an important role in the antidysrhythmic efficacy of these compounds which might be antagonized by ISA.

Adrenergic beta-Antagonists↗
PubMed1982

Antigen-induced acceleration of automaticity in electrically depolarized ventricular myocardium of sensitized guinea pigs.

Alterations in the membrane potentials during anaphylactic reactions were studied in ventricular muscle obtained from actively sensitized guinea pigs. The preparation was depolarized by constant current in a sucrose gap chamber to induce repetitive automatic action potential discharges (RAD) from the reduced membrane potentials (-60 to 0 mV). Application of specific antigen (human gamma-globulin, 6.8 X 10(-8) mol/L) markedly accelerated the firing frequency of the RAD. Overshoot and maximum rate of rise (Vmax) of the RAD increased during the initial 3 to 6 min of the antigenic challenge. The acceleration phase was followed by a long period of severe depression with marked reduction in the firing frequency of the RAD. These changes could be mimicked by an application of histamine (6.3 X 10(-7) mol/L) but were abolished in the presence of metiamide, a histamine H2-receptor antagonist (1 X 10(-5) mol/L). These findings indicate that an anaphylactic reaction transiently enhances the automaticity in electrotonically depolarized ventricular muscle, probably via the action of released histamine. Initial enhancement and later depression of the ectopic automaticity may be significant in the genesis of arrhythmias which occur during anaphylactic shock.

Action Potentials↗
PubMed1984

Rapid diagnostic DNA cytometry with an automatic microscope and a TV image-analysis system.

A TV-based image-analysis system (Leitz TAS plus) combined with a Leitz automatic microscope was used for rapid DNA cytometry for diagnostic purposes. Malignant or suspicious cells found by the cytopathologists in conventionally stained smears were automatically relocated and measured. A program for automatic detection and measurement of nuclear DNA content was developed. DNA data are processed by an algorithm for the diagnosis and grading of malignancy. This diagnostic procedure is performed in real time and yields highly reproducible results. With this equipment, diagnostic DNA cytometry may be introduced in the routine cytology laboratory. Our mode of application does not replace the cytopathologist, but assists him or her in cases of doubtful diagnosis and in the grading of malignant tumors.

Autoanalysis↗
PubMed1978

[Practical experiences with the Octopus automatic perimeter (author's transl)].

A statistical analysis comparing the results of more than 1000 visual field examinations carried out with the automatic perimeter Octopus and with a conventional Goldman-perimeter, clearly demonstrates the superiority of the automatic instrument in many respects: Apart from a higher precision of the perimetric measurements (smaller fluctuations), a better reproducibility of the results (larger correlation coefficients) is noticed. Due to great ease of operation of the automatic perimeter, the ophthalmologist is discharged from the time-consuming task of perimetric examinations.

Computers↗
PubMed1983

A preliminary evaluation of the use of an automatic impedance tympanometer in the diagnosis of otitis media with effusion in children: a report from the Dunedin Multidisciplinary Health and Development Research Unit.

Microscopic examination by two trained examiners, conventional impedance tympanometry by a trained audiometrist, automatic impedance tympanometry by a person with minimal training and puretone audiometry by trained audiometrists were compared in 468 ears, studied blind. There was complete examiner agreement in microscopic examination in 465 (99.3%) ears, minor disagreement in three (0.7%) ears. There was a more complex relationship between examination methods, with microscopic evidence of effusion being present in 88.2% of ears showing B tympanograms to conventional tympanometry and in 66.7% of ears to automatic tympanometry. Automatic tympanometry provides a reasonably accurate method of detecting middle ear effusion, but tends to overdiagnose this condition compared to alternate methods.

Acoustic Impedance Tests↗
PubMed1983

[Performance of a field test as proof of automatic cell analysis].

The screening by an automatic cell analyser (A) is justified, only if the false negative rate beta (A) is less than the false negative rate beta (M) of the manual method (M). A design is considered to get the numbers of ill persons who are "positive" by the manual method and "negative" by the automatic one, and vice versa "negative" by the manual and "positive" by the automatic. The sign test can be used to test the difference beta (A) - beta (M). Formulas for the necessary number n are given.

Autoanalysis↗
PubMed1983

Differentiation of normal and disturbed sleep by automatic analysis.

The main purpose of the present study was to develop an automatic hybrid system and evaluate its performance in the differentiation of normal and disturbed sleep. The study was carried out in roughly the following steps: At the beginning the quantity of five EEG waveforms, delta, theta, alpha, sigma and beta were examined with respect to sleep stages and their temporal distributions and inter-relationships throughout the nights in young 20-22 year-old, healthy individuals. These data were used as a basis for the choice of parameters for a sleep stage scoring program. Secondly, the sleep stage scoring software was developed using as test material three subject groups: about 10 years older controls, anonymous alcoholics and chronic alcoholics in the withdrawal phase. The last group was examined on two occasions, first in the initial withdrawal and then after two weeks' abstinence between the recordings. The sleep stage scoring program was evaluated in comparison with a visual sleep stage determination and its performance was also tested on the young normals. Attention was paid to three main points: First, how well does an automatic system imitate the visual classification of a human subject, when both the human and the computer classifications are compared side by side at a 20 s epoch level? Second, even if this comparison did not show a satisfactory agreement, could the computer classification still replace the visual sleep stage scoring when the objective is to describe the neurophysiological characteristics of the human whole-night sleep process or differentiate between normal and disturbed sleep. For this purpose it was examined, whether the values for the sleep stage parameters obtained by visual classification corresponded to those obtained by computer scoring and whether the differences found between the groups by manual methods could also be obtained by computer classification. The third goal was to see whether other measures than parameters received by sleep stage classification could be used for the differentiation between normal and disturbed sleep. In the present work only EEG waveform parameters and body movement activity were studied with this in mind. It was found that sleep can satisfactorily be classified in stages by automatic analysis if it is not markedly disturbed. The percentage agreement obtained for the three groups having practically normal sleep (young normals appr. 80%, older normals 77% and anonymous alcoholics 75%) was satisfactory and sufficient for clinical and experimental work.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

[Spatial parameters of the automatically reproduced QRS loop of the VCG in healthy subjects].

The findings of the VCG automatic construction in 55 healthy subjects with different axial and positional variants of ECG were analyzed . The applied method of the automatic corrected VCG construction has shown that QRS loop morphology coincides with the classical forms of VCG described before in healthy persons. The data of the automatic calculations of spatial characteristics demonstrated the orientation stability according to the angle--azimuth, max QRSxyz , S/2 QRSxyz and the integral vector-- AQRSxyz , i. e. independence of the azimuth value on the ECG axial and positional variants. The positional and rotational shifts regularly change the azimuth value in the spatial orientation of the initial (0.01"--0.02') and end (0.06") moment vector of depolarization, and the value of the angles of spatial vector elevation max QRSxyz , S/2 QRSxyz , AQRSxyz . In the normal intraventricular conduction, the orientations of max QRSxy , yz , xz are sufficiently informative in order to reveal the integral vector directions. The coincidence of S/2 QRSxy , yz , xz direction with that of AQRSxy , yz , xz in the two-polar loops indicates that S/2 QRSxy , yz , xz should be calculated to determine AQRSxy , yz , xz orientation. Indeed, in case of intraventricular conduction disorders, the AQRSxy , yz , xz calculation alone gives an idea of a resultant vector projection.

Adolescent↗
PubMed1981

[Computerized automatic management of the therapy of arterial hypertension].

On the basis of the propositions of the theory of automatic control and regulation, the authors developed the method, algorithm, and program of automatic controlled treatment of arterial hypertension by means of computers. It was conducted in 160 patients with hypertensive disease. Treatment was accomplished with reserpine, dopegit, hemiton, combination of these agents with each other and with diuretics, and with brinerdin. The effect was good in 70.6% and satisfactory in 21.9% of cases; no effect was produced in 7.5% of cases. The studies showed that the created algorithms and program make it possible to carry out effective controlled hypotensive therapy by means of computers. With the use of the developed method it was found that the tuning coefficients, and consequently, the dosages of the drugs necessary for reducing arterial pressure and its maintenance on the desirable preset level differ with the patients and in one and the same patient on different days of the treatment. Automatic controlled hypotensive therapy employing computers may be accomplished with a single agent and, whenever necessary, with a combination of several agents.

Adult↗
PubMedDate not supplied

[Automatic synchronization of growth of "Escherichia coli" (author's transl)].

Growth of bacteria in a fermentor is limited by an essential nutrient here inorganic phosphate. After starvation, the culture is diluted by an automatic device in such a way that the limiting nutrient concentration allows exactly one doubling. After 10 to 16 automatic cycles, which can be achieved overnight, synchronous bacterial cycles can be observed to occur spontaneously in non-limiting culture conditions, i.e. open systems. The operating procedures of the prototype are outlined. This "Automatic Synchronizer" has a capacity of about 0.1 g dry bacterial weight per cycle. Synchrony and homogeneity index are suggested, and applied to concrete examples of synchronous growth in closed and open systems. The maintenance of good synchrony in an open system throughout 6 cell cycles allows one to consider microbial growth and metabolism in a culture as reflecting the time schedule of the individual cell instead of being related to the statistical mean of a random cell population. The contradiction between the generation time variability observed under the microscope for individual clones and the amazing maintenance of good synchrony in our culture, is also discussed.

Bacteriological Techniques↗
PubMed1981

Automatic defibrillation in man. The initial surgical experience.

The automatic implantable defibrillator is an electronic device designed to detect and promptly correct malignant ventricular arrhythmias. Nineteen patients, all survivors of multiple cardiac arrests because of ventricular arrhythmias unresponsive to therapy, have undergone implantation of the automatic defibrillator. In seven patients who had had a previous cardiac operation, implantation was performed through a left lateral thoracotomy. A median sternotomy was used in five patients without a previous operation. In six patients cardiac procedures were performed concomitantly with defibrillator implantation. There were no operative deaths. The average follow-up is 6 months, the longest being 14 months. Following implantation, 47 episodes of malignant ventricular arrhythmias were documented. Twenty-six occurred spontaneously (17 of them outside the hospital); all were corrected with a single 25 joule pulse. Seventeen of 21 arrhythmias induced postoperatively were terminated. Although further validation is required, this study demonstrates that the automatic defibrillator is capable of diagnosing and terminating potentially lethal ventricular arrhythmias. Finally, implantation can be safely accomplished in an exceedingly high risk population.

Adolescent↗
PubMed1977

[Continuous automatic analysis of the ECG with the aid of a computer with cardiosignal input directly from the patient. 1. Isolation of the active signal of the ECG, identification and measurement of its elements].

Because when fed to an on-line computer the ECG information carries a good deal of noise, of prime importance is devising a method for representation and filtration of the useful asignal. It is shown that in order to separate the ueful signal with a protracted direct ECG input from the patient to a computer the use of the proposed modified method of coherent accumulation is advisable. This modification envisages a step-wise solution of the following problems: current diagnosis of arrhythmic contractions exclusion of arrhythmic contractions from the accumulation procedure, automatic search of the normal duration of the RR intervals, equalization of the RRh intervals duration, statistical averaging of the obtained quantum values. The devised modification of the coherent accumulation method, while considerably increasing the noise-immunity of the algorhythm, enables it to effect a direct long-term automatic analysis of the ECG at intensive care units. The identification and measurement of the ECG waves and intervals are done through and automatic selection of the curve elements search zones, finding local maxima and also of the commencement and end of waves by using the method of the "moving window" with an adaptive evaluation of the first signal derivative intensity.

Adolescent↗
PubMed1981

[Reliability of the bacterial identification tests and of antibiotic sensitivity tests made with automatic methods].

A "MS-2 Microbiology System" (Abbott) has been used to identify and to assess the susceptibility patterns of clinically isolated bacteria from highly compromised patients. Automatically obtained results by the analysis of 300 specimens were compared to those of traditional methods. The automated system was in good agreement with API (81%) while in 4% of the strains there were major discrepancies, and 5% of the experiments were carried out with slow growing bacteria which normally give poor results in automatic systems. Antimicrobial susceptibility testing was satisfactory in 84% of the specimens with 7% of minor discrepancies and 9% of major ones. The evaluation of MIC for slow growing organisms like Haemophilus, Diplococcus and anaerobes belonging to the Bacteroides genus, was the same using either automatic or standard procedures.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Quality changes in iced shrimps (Pandalus borealis). II Changes in the contents of trimethylamine oxide and volatile nitrogen bases during automatic boiling and peeling (author's transl)].

Post mortem trimethylamine oxide (TMAO) in marine animals is reduced to trimethylamine (TMA), and the degradation of proteins causes an increase in the ammonia (NH3) content. During ice-storage NH3 and TMA usually make up the major part of the total content of volatile nitrogen bases (TVN) which are formed during the degradation process. The formation of TMA and NH3 is probably caused mainly by bacterial enzymes. The contents of TMA and TVN in marine fish and shrimps are important objective criteria in supporting organoleptic examinations of such raw materials. During automatic boiling, peeling and rinsing processes in shrimp factories, some of these water-soluble and volatile compounds will be extracted by the boiling water and possibly evaporated. In this investigation we have attempted to estimate the loss of TMAO, TMA and TVN in shrimp muscle during this automatic processing. The investigation includes experiments in the laboratory (Table I, Figure 1) and in two factories (Table II-III, Figure 2-3). The results show that about 50% of the contents of TMAO-N, TMA-N and TVN probably will be lost from the shrimps during automatic processing. Adding approximately 100% TMA-N and TVN to the analysed contents in boiled, peeled and rinsed shrimps will therefore probably give the same level of these compounds as that found in the raw shrimps used. An accurate measurement of the TMA- and TVN-content in shrimp produced under known condition in North-Norwegian shrimps factories could give an objective indication of the quality of the raw shrimps used. In accordance with Norwegian shrimp regulations, only the fresh, healthy shrimps are allowed to be produced.

Food Handling↗
PubMedDate not supplied

An animal model for testing automatic defibrillators.

A promising therapy for ventricular fibrillation--a life-threatening cardiac arrhythmia--is implantation of an automatic defibrillator. A critical component of such a device is the system that detects the presence of ventricular fibrillation. Automatic systems for detecting ventricular fibrillation have been tested with arrhythmias produced by electric shocks in normal canine hearts, but have not been tested with spontaneous arrhythmias in hyperirritable hearts. We have developed an animal model to create arrhythmias without electrical stimulation and have used it to test our automatic defibrillator. This model permits evaluation of both reliability to diagnose VF and reliability to reject other tachyarrhythmias.

Animals↗
PubMed1980

The mechanism of barium-induced automaticity in ventricular muscle fibers.

When 2 mM BaCl2 was applied to dog ventricular muscle fibers that never showed a pacemaker activity under physiological conditions, muscle fibers depolarized to -46 mV and developed spontaneous activity. This spontaneous activity exhibited slow upstroke velocity and prolonged plateau of action potentials. The frequency of the Ba2+-induced automaticity was dependent on external Ca2+ concentrations and increased with a higher external Ca2+ up to 7.2 mM. The automaticity was abolished in Na+-free solution, high K+ (21.6 mM) solution, and the presence of verapamil. Membrane currents after Ba2+ application were shown to decrease in the steady state current and to increase in the slow inward current. The analysis of changes in the steady state current current revealed a decrease in the background K+ current, but no changes or later increase in the time-dependent K+ current after prolonged exposure to Ba2+. From these results, it is concluded that the Ba2+-induced automaticity is brought about by the decrease in the background K+ current, the increase in the slow inward current, and the activation of the time-dependent K+ current.

Animals↗
PubMed1981

Automatic chromosome analysis. II. Karyotyping of banded human chromosomes using band transition sequences.

Human chromosomes, represented by band transition sequences, chromosome area, centromeric index by area and centromeric index by density, were karyotyped by computer. A reference set of chromosomes provided frequencies of occurrence of each density class and difference class of the band transition sequence as well as of each of the three global features. The karyotyping program was designed to handle all metaphases, even those from which severely bent and overlapped chromosomes were excluded. In one experiment, 21 metaphases were karyotyped on the basis of a reference set and the results were compared with earlier results of visual analysis of band transition profiles developed from band transition sequences: 0.8% errors were made in the visual experiment and 1.4% errors were made in the computer based experiment. In a second experiment, 179 metaphases were divided into reference and test sets and karyotyped by computer with an error rate of 3.4%. By further analysis it was found that metaphases with many misclassified chromosomes could often be automatically distinguished from metaphases with few errors. Thus by automatic rejection of 7% of the metaphases the error rate could be reduced to 2.6%. The computer program for chromosome karyotyping will now be implemented in a semi-automatic system for practical clinical chromosome analysis.

Chromosome Banding↗