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At least 1,099 records · Page 61Linked to original sources
PubMed1987

Compared efficacy of quinidine, amiodarone and diltiazem on both nomotopic and ectopic automaticity in the rat heart.

The effect of quinidine, amiodarone and diltiazem have been studied on both nomotopic (isolated right atria) and ectopic automaticity (induced by a local injury in the isolated right ventricle) in the rat heart. The efficacy of these three drugs, measured by the corresponding ID25, was diltiazem greater than quinidine greater than amiodarone on atrial rate and amiodarone greater than quinidine greater than diltiazem on ectopic ventricular automaticity. A depression of isolated right atria rate (sinus node function) could be regarded as an adverse effect of the drug tested (toxicity-index). On the other hand, the reduction of ectopic ventricular automaticity by the antiarrhythmic agent is considered as desired effect (effectiveness-index). We conclude that this method might be useful to evaluate the effectiveness-toxicity ratio, as a first experimental step in the development of new antiarrhythmic drugs with a direct action on cardiac tissue.

Amiodarone↗
PubMed1987

[Place of automatic oxytocin perfusion devices in the artificial induction of labor].

Automatic and self-regulated ocytocin perfusion sets, currently available, are able to precisely analyze the uterine activity in 15 minutes and automatically reduce the ocytocin output when a stable and effective uterine activity is obtained. The authors report the results of 41 inducements with the Autosoma pump and compare them with 358 inducements with manually controlled pumps. The duration and the amount of ocytocin perfused with Autosoma are comparable to the results obtained with manually controlled pumps. The frequent release of Autosoma alarms at the beginning of the experiment partially explains the lack of advantages of the automatic perfusion set.

Female↗
PubMed1987

Comparative effects of adenosine triphosphate on automaticity and conduction in human cardiac tissue.

Adenosine triphosphate is effective in terminating re-entrant supraventricular arrhythmias, but previous studies have demonstrated a wide range for therapeutic doses. We determined dose response curves for ATP (Striadyne) in order to determine the mechanism of variability in response to this agent. In addition, this enabled comparison of AV nodal, SA nodal intraventricular and accessory pathway properties. Incremental bolus doses of ATP were administered to patients following electrophysiologic studies. Sinus node effects were determined by the change in spontaneous sinus cycle length (n = 7). AV node response was assessed by measuring the AH interval during atrial pacing at CL 400 msec (n = 7). The effects of intraventricular automaticity were assessed by observing the spontaneous cycle length (n = 1), and accessory pathway effects were observed during atrial or ventricular pacing (n = 2). ATP prolonged sinus cycle length in all patients (delta CL 295 +/- 91 msec) with a mean effective dose of 0.84 mg (range 0.5-8.0 mg). ATP prolonged AH interval with a mean effective concentration of 2.0 mg. The mean dose to produce AV block was 4.6 mg. In contrast, a ventricular escape rhythm failed to show cycle length prolongation but only showed cycle length shortening. The accessory pathways did not demonstrate block even in high doses. Thus, adenosine triphosphate selectively affects the sinoatrial node and AV nodal tissue with inhibitory effects on automaticity and conduction. The effect on intraventricular automaticity was excitatory, with minimal effects observed in accessory pathways.

Adenosine Triphosphate↗
PubMed1987

[Automatic implantable cardioverter-defibrillator (AICD) and antitachycardia pacemaker (Tachylog 651) in the treatment of ventricular tachyarrhythmias].

For the electrotherapy of refractory ventricular tachycardia the automatic implantable cardioverter-defibrillator (AICD) and antitachycardia pacemaker are available. The long-term use of antitachycardia pacing is still limited by the potential risk of acceleration to ventricular fibrillation. To combine the advantages of antitachycardia pacing with back-up defibrillation, we evaluated the use of an antitachycardia pacemaker with the automatic defibrillator. The AICD was implanted in 13 patients with a mean age of 62 years (from 46 to 75 years); six of them with recurrent ventricular tachycardia (170 +/- 16 per minute) which could reliably be terminated by overdrive pacing, received also an antitachycardia pacemaker (Tachylog 651). The underlying cardiac disease was coronary heart disease in 11 patients and cardiomyopathy in 2 cases. All patients had survived 1 to 6 cardiac arrests and had not responded to 6 +/- 1.5 antiarrhythmic drugs. For antitachycardia pacing we used burst stimulation with 4 to 6 stimuli and coupling intervals from 260 to 300 ms. During the follow-up period of 12 +/- 2 months, 83% of 744 tachycardias could be terminated by burst stimulation, according to the diagnostic data of the pulse generator. If the pacemaker failed to terminate or in case of acceleration (three patients), the automatic countershock of the AICD (5-42 per patient) restored sinus rhythm. In seven patients with high rate tachycardia, 2 to 69 AICD discharges occurred. No patient died suddenly, but three died due to underlying disease and one because of a pneumonia postoperatively. Future antitachycardia devices should be flexible with regard to detection and termination modes, combining antitachycardia pacing with back-up defibrillation.

Electric Countershock↗
PubMed1986

The effect of skin cleansing agents on ethanol results measured with the Du Pont automatic clinical analyzer.

The effect of various prepackaged skin cleansers on the results of serum ethanol analyses performed with the Du Pont automatic clinical analyzer has not been previously reported. When added directly to serum in concentrations of either 0.625 or 1.56% (v/v), neither polyvinyl-pyrrolidone iodine nor benzalkonium chloride affected the ethanol results. The cross-reactivity of isopropanol with the automatic clinical analyzer ethanol procedure was 3.9%. The greatest interference in the measured ethanol concentration was from the addition of green soap tincture, which contained 30% ethanol. The effect of improper phlebotomy technique on ethanol measurements was also investigated by performing venipunctures through a pool of 100% ethanol on the skin. No ethanol was detected in these samples unless an ethanol-soaked sponge was pressed over the venipuncture site while the needle was withdrawn from the skin. When correct phlebotomy technique is used, skin cleansing agents should not affect the results of ethanol measurements determined with the Du Pont automatic clinical analyzer.

Blood Specimen Collection↗
PubMed1986

Automatic digital image analysis for identification of mitotic cells in synchronous mammalian cell cultures.

Mitotic frequency in a synchronous culture of mammalian cells was determined fully automatically and in real time using low-intensity phase-contrast microscopy and a newvicon video camera connected to an EyeCom III image processor. Image samples, at a frequency of one per minute for 50 hours, were analyzed by first extracting the high-frequency picture components, then thresholding and probing for annular objects indicative of putative mitotic cells. Both the extraction of high-frequency components and the recognition of rings of varying radii and discontinuities employed novel algorithms. Spatial and temporal relationships between annuli were examined to discern the occurrences of mitoses, and such events were recorded in a computer data file. At present, the automatic analysis is suited for random cell proliferation rate measurements or cell cycle studies. The automatic identification of mitotic cells as described here provides a measure of the average proliferative activity of the cell population as a whole and eliminates more than eight hours of manual review per time-lapse video recording.

Animals↗
PubMed1986

[Evaluation of an automatic system for the electrophoretic fracturing of serum proteins and a comparison with the manual method].

A few weeks ago, the automatized apparatus known as Hite System 600 for the electrophoretic separation of serum proteins was put into use for the first time in our laboratory. In order to evaluate the two methods, the automatized one and the previously used manual one, we conducted a series of quality checks concerning both accuracy and precision. In addition, the correlation between the two methods was studied. Our results demonstrated that the automatized method was more precise even though the two methods showed a perfect overlap.

Automation↗
PubMedDate not supplied

The value of automatic analysis for quantitative electromyography.

The value of automatic analysis for quantitative electromyography. Acta Physiol. Pol., 1979, 30 (2): 231--239. The authors describe the automatic analysis of EMG records by means of minicomputer ANOPS-101. Computer works on-line during EMG examination, being directly connected to the output of electromyograph. During slight voluntary muscle contraction 3 histograms could be obtained--namely: distribution of MUAP duration, number of their phases and their amplitudes. During maximum voluntary contraction two more histograms could be obtained--namely: distribution of amplitudes of spikes and distribution of intervals between spikes. These five histograms are displayed on the screen and the mean values are automatically calculated. As a result all quantitative EMG data are obtained which are sufficiently accurate for differentiation between pathological and normal recordings and which help to distinguish the myogenic atrophy from neurogenic one.

Action Potentials↗
PubMed1986

[Automatic analysis of needle EMG in the differential diagnosis of neuromuscular diseases].

A total of 112 muscles were studied in 68 patients with different neuromuscular diseases (7 nosological forms). The study was performed using an original programme of an automatic analysis of needle real-time electromyography and a specially designed automatic system on the basis of Soviet microcomputer "Electronika-60". On the basis of an automatic analysis of 17,834 potentials the authors identified 1,619 individual potentials of motor units. Measurement of all parameters (amplitude, duration, the number of phases in the potential and area) and calculation of correlations between individual parameters revealed significant differences of the mean values of the above parameters for each group of patients.

Adolescent↗
PubMed1986

Timing of automatic contralateral groin exploration in male infants with unilateral hernias.

The effect of using 6 months as the cutoff age for automatic exploration of the asymptomatic contralateral side in male infants undergoing inguinal herniorrhaphy was studied by evaluating the operative findings and follow-up of 300 consecutive male infants admitted for symptomatic unilateral groin hernias. Males under the age of 6 months were automatically explored on the contralateral asymptomatic side. Those between 6 and 24 months underwent repair of only the symptomatic presenting side. The negative exploration rate in the 121 infants less than 6 months was 38 per cent. The return rate for contralateral exploration in children between 6 months and 2 years was 1 per cent. Follow-up ranged from 1 to 5 years. This data suggests that lowering the age for automatic exploration of the male contralateral groin to 6 months does not increase the rate of positive findings on the asymptomatic side. Nor does it appreciably increase the rate of later required contralateral operations.

Follow-Up Studies↗
PubMed1986

An automatic pneumatically driven autotransfusion system: a hematologic evaluation in dogs.

An automatic, pneumatically driven autotransfusion system (ATS) was developed because ATSs driven by roller pumps are complicated to set up and require an experienced operator. In this ATS blood is aspirated into a cardiotomy reservoir by means of a constant vacuum applied on that reservoir. Damage to blood cells is reduced by an electronic device that regulates an automatic tubing clamp in the suction line to prevent suction of air along with blood (controlled suction). The blood is reinfused by a diaphragm pump driven by alternating vacuum and compressed air. The frequency of this pump is regulated by a level sensor in the cardiotomy reservoir to maintain a constant preset level. When we tested this automatic ATS in dogs, platelet function and platelet numbers substantially recovered after a dip during an autotransfusion period of 1 hour. Advantages of this ATS are that it causes only minor blood damage, it does not require a specially trained operator, and it is ready to use in every operating room. The diaphragm pump can be made disposable and integrated in the bottom of a cardiotomy reservoir.

Animals↗
PubMed1985

Amrinone effects on electromechanical coupling and depolarization-induced automaticity in ventricular muscle of guinea pigs and ferrets.

The effects of the cardiotonic agent, amrinone (0.05-4 mM), on electrical and mechanical activities of ferret and guinea-pig papillary muscles were studied using current and voltage clamp (single sucrose gap) techniques. In current clamp studies, amrinone increased, in a dose-dependent manner, contractile force elicited by action potential in both species. Depolarization-induced automaticity was facilitated in ferret muscles at all maximum diastolic potentials between -70 and -15 mV. Facilitation of automaticity in guinea-pig muscles occurred only at potentials more negative than -35 mV and was suppressed at more positive potentials. Cimetidine (10 microM) partially reversed the effects of amrinone on automaticity in both species. In voltage clamp studies, amrinone increased the slow inward current. Steady-state outward current was increased in guinea-pig but not in ferret muscles. A dual effect of amrinone on tension was observed. Amrinone was found to increase phasic tension of ferret papillary muscles only for depolarizations lasting less than 250 to 300 msec. For longer depolarizations, amrinone decreased the phasic tension (in a dose-dependent manner), whereas the tonic tension was not modified. The decrease as well as the increase in tension was associated with an increase of the slow inward current. The results suggest that amrinone may be arrhythmogenic and may have an intracellular action at the sarcoplasmic reticulum level (partial inhibition) in addition to its action on the calcium current.

Action Potentials↗
PubMed1985

[Evaluation of the performance of an automatic coagulation tester: the Electra 700].

The Electra 700, an automatic coagulation tester recently available in France, was investigated for its performance on routine tests: Quick's test, APTT, thrombin clotting time test, assay of fibrinogen and prothrombin complex factors. Reproducibility was exceptionally good for Quick's test (CV less than 1%), excellent for the other tests (CV less than 3%), acceptability of the various commercial reagents very good, and standard linearity excellent. There was close correlation with manually obtained (electromagnetic B.M.) or semiautomated (KC 10) results (0.9948 to 0.9345). The apparatus is entirely automatic once specimens have been loaded, and it is particularly adapted to dealing with long series of specimens (60 samples). Its original loading system makes it possible to carry out two types of test concurrently, as well as to insert emergency tests. Economically, the cost of disposables and "reagent loss" is satisfactory; however, all tests are carried out relatively slowly, though this is compensated for by the fact that the reactions are completely automatic.

Blood Coagulation Tests↗
PubMed1979

[New aspects of conventional tomography with special reference to automatic exposure control].

Automatic exposure control in tomography requires control of dose output whereas in survey technique dose is controlled. Automatic exposure not only facilitates work load but also improves image quality by balancing regions of differing density. High control-frequency and -sensibility are essential requirements; otherwise unsatisfactory findings i.e. erraneous images may result in particular when the time for a tomographic cycle is short. These high requirements exceed the performance margin of conventional automatic exposure control systems in which dose control is achieved by control of tube heat. A combined tube-current- and voltage-control with regard to primary voltage phase as used in units designed lately serves all routine use needs and delivers high quality tomograms.

Automation↗
PubMed1979

[Automatic recognition of hemisphere-borderlines in cerebral radionuclide angiography (author's transl)].

The diagnostic value of brain perfusion studies with radionuclides is based upon the careful determination of intracerebral vascular supply areas in sequential scintigraphic frames. This paper describes an automatic algorithm to determine cerebral hemisphere-borderlines (Regions of Interest). In 134 randomized brain perfusion studies, regions of interest were set by three techniques: automatically by a computer program at the beginning of the venous phase, automatically by using all images derived from the total bolus passage (40 sec.), and manual marking with a light pen at the beginning of the venous phase. A good correlation of these different techniques was obtained (r = 0.87). Furthermore, we found the bilateral perfusion index independent within a wide range, from the size of the marked regions and the quality of the injected indicator bolus. Time saving and lesser carefulness, concomitant with higher precision and reliability, in addition to the standardisation of the marking technique increase the diagnostic value of cerebral radionuclide angiography.

Brain↗
PubMedDate not supplied

An automatic spindle analysis and detection system based on the evaluation of human ratings of the spindle quality.

An evaluation of the spindle quality ranked by experienced human raters is described. The pattern discriminating criteria obtained from this evaluation are used for an automatic system based on the complex demodulation method. The performance of this automatic system is compared with both the human visual scoring and with a second automatic system employing phaselocked loop techniques. The performance of the complex demodulation is satisfactory. It also detects spindles buried in slow waves. It is not sensitive to the age of the subject. This method opens possibilities for research of either temporal or chemical (drugs etc.) effects on the characteristics of rhythmic activity, without being hampered by the arbitrary EEG jargon "alpha" or "sigma".

Adult↗
PubMed1984

Pacemaker automatism activity in atrioventricular valves and its possible role in producing cardiac arrhythmias.

In the atrioventricular valves of the hearts of 161 rabbits the authors found permanent spontaneous automatism activity. Isolated leaflets of these valves were examined with the aim to detect the electrophysiological and morphological characteristics of pacemaker formations constituting the substrate of spontaneous automatism. It was found that these formations consist of pacemaker cells of three types: P-cells, cells of intermediary type and Purkinje-type cells. Further, it was found that a decisive role in the genesis of spontaneous excitations of pacemaker cells of AV valves is played by the slow Na-Ca channel. Examination documented good innervation of the pacemaker formations, and the specific effect of mediators [acetylcholine, adrenaline, noradrenaline] on their automatism was investigated. Investigations on isolated rabbit hearts evidenced that impulses originating from the heterotopic excitation focus, localized in the AV valve leaflets, can be conducted into other compartments of the heart and can cause cardiac arrhythmias.

Acetylcholine↗
PubMedDate not supplied

[Automatic gas exchange control of the autotrophic component in a life support system for heterotrophic organisms].

The paper describes an automatic gas exchange control system for the autotrophic component in the life support system of heterotrophic organisms. The paper shows how the automatic control system of the autotrophic component (wheat) can be combined with that of the heterotrophic component (four white rats). The study has demonstrated a high efficiency of the automatic gas exchange control system of plants integrated with animals. The study has also provided balance characteristics of the integrated gas exchange in the plant-animal system.

Animals↗