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PubMedDate not supplied

A method for measurement of frequency, modulation characteristics and timer accuracy of ultrasonic therapy equipment.

A method is described for measuring the ultrasonic frequency, modulation data, and exposure time of ultrasonic therapy equipment be detection and analysis of the ultrasonic radiation rather than direct measurement of the electrical rf signal. The equipment used in performing these measurements consists of a receiving piezoelectric transducer, ana electron counter/timer designed to accept and process the detected ultrasonic signal, and an oscilloscope.

Ultrasonic Therapy↗

PubMed1993

[Effects of ultrasonic energy on blood clots in vitro].

Ultrasound may be used to dissolve arterial and venous thrombi. Its effects depends on the mode of ultrasonic vibration and on the length of the guide wire. The authors studied the in vitro effects of an ultrasonic angioplasty device coupled with a 130 cm long titanium flexible guide wire. The system comprises an automatic scanning function to determine the optimal frequency of resonance and works in the continuous mode of emission. Sixteen thrombi were studied of which 8 were acellular and 8 whole blood. In each group, 4 were treated in association with streptokinase and 4 by ultrasound alone. The ages of the thrombi in each subgroup were 1, 3, 7 and 15 days. All the thrombi were dissolved in 6 minutes or less (3'15" +/- 1'35") at an average optimal frequency of resonance of 19,444 Hz. Ninety six per cent of the debris had a diameter less than 10 microns. Less than 1% of the debris had a diameter larger than 100 microns. These large particles were observed in cellular thrombi and were almost completely absent in dissolved acellular thrombi. They were very fragile. The dissolution of the thrombi was not accelerated by the association of streptokinase. The ultrasonic energy did not induce D-dimer production and its action was probably due to cavitation. Ultrasonic energy could provide an alternative treatment for thrombotic vascular occlusion provided that more flexible guide wires could be designed.

Humans↗

PubMed1986

Segmental hepatic resection utilizing the ultrasonic dissector.

Hepatic resection continues to become a more widely accepted therapeutic modality, with increased use as improved imaging modalities more precisely define the nature and extent of various liver abnormalities. The surgical anatomy of the liver indicates that there are eight segments with single or multiple segmental resections able to be performed. The use of the ultrasonic dissector facilitates the performance of transparenchymatous segmental resection without obtaining vascular inflow or outflow control. This report describes the segmental anatomy of the liver and the use of the ultrasonic dissector. Thirteen patients have undergone segmental hepatic resection with the ultrasonic dissector. Five patients had cirrhosis. Mean +/- 1 SD operative time required for segmental resection was 128 +/- 57 minutes, and blood loss was 830 +/- 623 mL. Utilization of the ultrasonic dissector to perform segmental hepatic resection may increase our versatility in the management of various hepatic and biliary tract diseases.

Adult↗

PubMed1996

Hepatectomy with an ultrasonic dissector for hepatocellular carcinoma.

This study compared the results of hepatectomy for hepatocellular carcinoma (HCC) using an ultrasonic dissector with those of a combination of the crushing clamp and finger fracture techniques. The crushing clamp and finger fracture method was used from 1989 to 1992 in 96 patients (group 1) and the ultrasonic dissector from 1993 to 1994 in 69 patients (group 2). Data from these two sets of patients were collected prospectively. The groups were comparable in terms of preoperative liver function, tumour size and stage, and the incidence of cirrhosis. Major hepatectomy was performed in 69 patients (72 per cent) of group 1 and in 52 (75 per cent) of those in group 2. Use of the ultrasonic dissector resulted in lower mean (s.e.m.) blood loss (group 1 3.4(0.4) litres versus group 2 2.4(0.2) litres, P = 0.02), lower mean (s.e.m.) blood transfusion requirement (2.2(0.2) versus 1.2(0.2) litres, P = 0.001) and more patients not requiring blood transfusion (8 per cent of group 1 versus 32 per cent of group 2, P = 0.0001). Postoperative complications occurred in 45 patients (47 per cent) of group 1 and 19 (28 per cent) of those in group 2 (P = 0.012). There were no deaths in group 2 whereas the hospital mortality rate in group 1 was 16 of 96 (17 per cent) (P = 0.0004). A wider tumour-free resection margin (mean(s.e.m.) 1.2(0.1) versus 0.9(0.1) cm, P < 0.05) and lower serum bilirubin level throughout the postoperative period were also observed in group 2 patients. The ultrasonic dissector is better than the crushing clamp and finger fracture technique in hepatectomy for HCC.

Blood Loss, Surgical↗

PubMed2005

Randomized trial of traditional dissection with electrocautery versus ultrasonic fundus-first dissection in patients undergoing laparoscopic cholecystectomy.

BACKGROUND: In laparoscopic cholecystectomy dissection can be with monopolar electrocautery or with ultrasonic shears, and can start at the triangle of Calot or at the fundus of the gallbladder. METHODS: Thirty-seven patients undergoing laparoscopic cholecystectomy were randomized to electrocautery dissection from the triangle of Calot and 43 to fundus-first dissection with ultrasonic shears. All procedures were strictly standardized, and patients and their postoperative carers were blinded to the operation performed. RESULTS: Ultrasonic fundus-first dissection was associated with a shorter duration of operation (mean 46 versus 61 min), fewer overnight hospital stays (two versus eight), lower pain scores 4 and 24 h after surgery, less nausea at 2, 4 and 24 h, and a shorter period of sick leave (mean 5.5 versus 9.3 days) compared with electrocautery from the triangle of Calot. CONCLUSION: Ultrasonic fundus-first dissection during laparoscopic cholecystectomy was quicker and associated with less nausea and pain than electrocautery dissection from the triangle of Calot.

Adult↗

PubMed1985

Effects of atherosclerotic lesions on ultrasonic beam and CW Doppler signals.

Doppler ultrasound has been shown to be a useful clinical tool in the noninvasive detection of vascular stenoses, occlusion, or plaques. The presence of atherosclerotic lesions in blood vessel walls can distort the Doppler ultrasonic signal, producing inverted or biphasic tracings. This observation, in fact, has been used frequently as a criterion for the diagnosis of plaque formation and calcification of these lesions. To define the source of this distortion, we have examined the effects of various types of atherosclerotic lesions on the transmitted ultrasonic beam generated by a continuous wave (CW) Doppler ultrasonic probe. These results are compared to the Doppler flow tracings obtained by a CW ultrasonic Doppler flowmeter from blood vessels with overlaying lesions in a mock flow system. It is concluded that severe distortion in the form of beam refraction or diffraction can be produced by calcified lesions, resulting in biphasic or inverted flow signals.

Arteriosclerosis↗

PubMed2003

Cavitation-induced pyrolysis of toxic chlorophenol by high-frequency ultrasonic irradiation.

p-Chlorophenol (4-CP) is a recalcitrant organic pollutant that is biologically toxic in industrial wastewater. A high-frequency ultrasonic device operated at 1.7 MHz was designed and used successfully to degrade 4-CP. Iodine liberation in the KI aqueous solution confirmed that effective cavitation occurred under the high-frequency ultrasonic irradiation. No products or intermediate products were detected following the sonochemical degradation by 1H-nuclear magnetic resonance spectrum and mass spectrum after ultrasonic irradiation. It was concluded that the dominant degradation mechanism was high-temperature pyrolysis to inorganic products in ultrasonic cavities rather than free-radical oxidation.

Chlorophenols↗

PubMed1988

The influence of psychotropic drugs on the ultrasonic calling of mouse pups.

The influence of a range of commonly used psychotherapeutic drugs on the ultrasonic calling of mouse pups was assessed. The major tranquilizers chlorpromazine and haloperidol were without effect. Whereas tranylcypromine and imipramine were also inactive, amitriptyline suppressed the rate of calling. Some anxiolytic compounds such as meprobamate and amobarbital were without influence, although others such as diazepam, chlordiazepoxide and ipsapirone decreased the number of calls. The influence of these drugs on body temperature was measured, as it is known to markedly influence the rate of ultrasonic calling. Although six out of ten drugs decreased body temperature, there was no evidence that this was related to the rate of ultrasonic calling. The possibility that the recording of ultrasonic calls could be used to screen for psychotropic activity is discussed.

Animals↗

PubMed2005

Ultrasonically nebulized distilled water prevents exogenous histamine hyperreactivity in Toxocara canis-infected mice.

OBJECTIVE: This study examines the effect of ultrasonically nebulized distilled water inhalation on the systemic histamine hyperreactivity of Toxocara canis-infected mice. METHODS: Uninfected and T. canis-infected mice received an intravenous sublethal dose of histamine and lethality rates were documented. At 24 days post infection, infected mice received ultrasonically nebulized distilled water inhalation for 1 h. Twenty-four hours later histamine levels were determined in bronchoalveolar lavage fluid as well as histamine lethality and toluidine blue-stained mast cell number in the lung. RESULTS: T. canis-infected mice showed increased lethality after exposure to histamine in comparison to uninfected mice. Ultrasonically nebulized distilled water inhalation prevented histamine-induced lethality and reduced toluidine blue-stained mast cell numbers in the lung. CONCLUSIONS: The correlation between decreases in stained mast cells in the lung after ultrasonically nebulized distilled water inhalation and inhibition of histamine-induced lethality in these animals suggests participation of mast cells in the phenomenon and could be helpful in understanding the mechanisms of hyperreactivity during helminth parasite infections.

Anaphylaxis↗

PubMed2000

Ultrasonically activated scalpel is an effective tool for cutting the pancreas in biliary-pancreatic surgery: experimental and clinical studies.

The ultrasonically activated scalpel, a new tool for cutting and coagulating tissue, uses high-frequency ultrasonic vibrations, and has been widely employed in the field of laparoscopic surgery. We evaluated its usefulness for cutting the pancreas in biliary-pancreatic surgery. We planned experimental and clinical studies using an ultrasonically activated scalpel (harmonic scalpel) for cutting the pancreas. The harmonic scalpel was set up at a power level of 3 (75% of full power) in the knife mode. In the experimental study, using dogs, cutting of the pancreas with the harmonic scalpel resulted in significantly less bleeding and significantly less histological tissue damage to the cut stumps than cutting of the pancreas with an electric or a regular scalpel. In the clinical study: (1) the hemostatic effect of the harmonic scalpel was excellent or good in any condition of the pancreas; (2) of 50 stumps of the main pancreatic duct cut with the harmonic scalpel, the stump was easily found in 48 (96%), while ultrasonography was necessary to find the remaining 2 stumps in soft pancreas; (3) in 41 anastomoses (29 soft and 12 hard pancreas) there were no postoperative pancreatic fistulae. These results indicate that the ultrasonically activated scalpel is an effective tool for cutting the pancreas in biliary-pancreatic surgery.

Animals↗

PubMed2006

Applicability of an ultrasonic nebulization system for the airways delivery of beclomethasone dipropionate in a murine model of asthma.

PURPOSE: We have assessed the use of an ultrasonic nebulization system (UNS), composed of ultrasonic nebulizer and diffusion dryer filled with charcoal, for the effective delivery of beclomethasone to the airways in a murine asthma model. METHODS: Solution of beclomethasone in ethanol was aerosolized using an ultrasonic nebulizer. Passage of the aerosol through a drying column containing charcoal and deionizer produced dry beclomethasone particles. Particles were delivered to BALB/c mice placed in a whole-body exposition chamber 1 h before intranasal challenge with ovalbumine. Efficacy of beclomethasone delivery was evaluated by examining bronchoalveolar lavage fluid (BALF) cytology. RESULTS: Effect of three UNS system parameters on aerosol particle size was investigated. The critical parameter affecting the size of dry particles was beclomethasone concentration in aerosolized solution and solution flow rate while power level of ultrasonic nebulizer generator had no effect. Administration of beclomethasone at calculated dose of 150 microg/kg to mice significantly decreased total cell number and relative eosinophil number in BALF. CONCLUSIONS: The UNS system produces a monodisperse aerosol that can be used for inhalative delivery of poorly water soluble substances to experimental animals. The UNS system minimizes formulation requirements and allows rapid and relatively simple efficacy and toxicity testing in animals.

Algorithms↗

PubMed1985

Ultrasonic absorption in tobacco mosaic virus and its protein aggregates.

The structural fluctuations specific to self-assembled biological systems have been investigated further with ultrasonic techniques by using two strains of tobacco mosaic virus (TMV), as well as the helical aggregate of the common strain protein and subassemblies of it. We confirmed our earlier conclusion that protein assemblies exhibit specific structural fluctuations detected in ultrasonic experiments. As in spherical viruses, the fluctuations exhibited by the protein aggregates having a quaternary structure similar to that of the virion were modified in the virus by interaction with the RNA strand. It is unlikely that the origin for the observed effect is due either to: (1) the difference in local mobility of the segment 89 to 113 of the polypeptide chain in TMV and in the helical aggregate on the one hand, and in smaller aggregates, on the other hand; or (2) a local fluctuation associated with proton transfer reactions or ion-pair interactions. The most remarkable feature in the TMV system is the fact that the two-ring disk showed no excess of ultrasonic absorption with respect to the A-protein oligomer, while a large increase of ultrasonic absorption was observed in the rod-like aggregate that had undergone the disk-helix transition.

Hydrogen-Ion Concentration↗

PubMed1988

Ultrasonic vocalization in response to unavoidable aversive stimuli in rats: effects of benzodiazepines.

The effects of two benzodiazepine derivatives (diazepam, 0.5-1 mg/kg; alprazolam, 1.25-2.5 mg/kg) on ultrasonic calling elicited in adult rats by unavoidable aversive stimuli (footshocks) were investigated. The results show that either diazepam or alprazolam affected the duration of ultrasonic calls. In particular, a significant decrease in the length of ultrasounds was found in the group of animals treated with these benzodiazepines. The effects of diazepam were counteracted by the benzodiazepine-antagonist Ro 15-1788. On the other hand, neither a neuroleptic agent, such as haloperidol (0.5-1 mg/kg), nor an antidepressant, such as desipramine (5-10 mg/kg) influenced the parameters of ultrasonic emission in this experimental situation. The present results suggest that ultrasonic vocalization in response to unavoidable aversive stimuli could be considered as a potential new tool for studying drugs with antianxiety properties.

Alprazolam↗

PubMed1986

Ultrasonically guided percutaneous and laparoscopic oocyte aspiration: a comparative study.

Oocyte collection for in vitro fertilization was performed in 105 cycles (65 patients) by ultrasonically guided percutaneous puncture (63 cycles) or laparoscopy (42 cycles). During the ultrasonically guided approach an open or closed needle system was used. During both ultrasonically guided and laparoscopic follicle aspiration, all visible follicles were punctured. The mean number of punctured follicles per cycle was comparable for both techniques. Despite a significantly higher mean number of oocytes per cycle harvested during laparoscopy, the mean number of embryos per cycle was not essentially different with the two techniques. Also no difference could be established between the ultrasonically guided open and closed needle systems.

Embryo Transfer↗

PubMed1987

Ultrasonic vocalization in rat pups: effects of early postnatal exposure to SCH 23390 (a DA1-receptor antagonist) and sulpiride (a DA2-receptor antagonist).

Early postnatal administration of SCH 23390 and sulpiride induced marked changes in the ultrasonic vocalization elicited by the removal of rat pups from their nest. In particular, SCH 23390 produced a significant increase in the length, as well as in the sound pressure level, of ultrasonic calls; moreover, a significant decrease in minimum and maximum frequency values was found in pups treated with this DA1-receptor antagonist. Sulpiride significantly reduced the rate of calling, as well as the pressure level of sounds, whereas it did not influence other parameters of the ultrasonic emission. These behavioural alterations seemed to be the consequence of an impaired functional maturation of the dopamine (DA) system; however, the different changes caused by SCH 23390 and sulpiride, respectively, suggest that DA1- and DA2-receptor populations could play a distinct role in the ultrasonic calling during early postnatal life.

Animals↗

PubMed1989

Temperature changes in thermoplasticized gutta-percha: a comparison of two ultrasonic units.

With the use of an extracted human tooth as in vitro model, this study measured temperature changes in the surface of gutta-percha while it was being ultrasonically thermoplasticized. Two sources of ultrasonic oscillation were used: a Cavitron 2001 ultrasonic unit with a file in a PR-30 insert and an ENAC ultrasonic unit with a plugger or file. Temperature elevation in the apical third of the tooth was minimal with either instrument (1.66 degrees C to 3.74 degrees C). The temperature rise in the middle third was higher with the ENAC unit, although probably still within clinically acceptable limits (range, 6.35 degrees C to 19.10 degrees C). The time taken for each unit to thermoplasticize the gutta-percha and reach a predetermined distance in the experimental model was recorded and defined as instrument efficiency. The Cavitron unit that had the PR-30 insert with a No. 25 file required 0.48 sec/mm, whereas the ENAC unit with a No. 25 file required 10.83 sec/mm and the ENAC unit with a plugger required 8.38 sec/mm. It appears that the Cavitron unit with a PR-30 insert was more than 22 times as efficient as the ENAC unit for thermoplasticizing gutta-percha under the experimental conditions used in this study.

Chemical Phenomena↗

PubMed1992

Ultrasonic vocalization of laboratory rats in response to handling and touch.

The goal of the study was to investigate the ultrasonic vocalization induced in freely behaving, naive rats by gentle touch with a human hand. Thirty-nine rats were tested in an unfamiliar experimental cage with repeatable hand touch. Vocalization appeared with an average latency of 4.6 +/- 5.0 s (SD). The nape of the neck was the most effective area, and after a couple of stimuli applied, 66.7% of rats emitted 21-32 kHz ultrasonic vocalization. It consisted of multiple series of long calls, about 70% of which exceeded 300 ms. The responses quickly habituated from session to session to extinction. Significantly more rats housed in single cages vocalized ultrasonically than animals housed in community cages. The long latencies of the vocalization, their appearance in multiple series to a single touch, and quick habituation to the stimuli indicate that 22 kHz ultrasonic vocalization of rats reflects a distress caused by a potential danger to the animal and it does not necessarily reflect physical discomfort or pain. This vocalization may, therefore, play an adaptive role in increasing chances of survival by conveying information about potential threats to other conspecifics.

Animals↗

PubMed1977

A high resolution ultrasonic microscope.

The construction and imaging capabilities of a scanning high resolution ultrasonic microscope are considered in this paper. Theoretical expressions for the resolution limits of the microscope and some of the most important properties of the ultrasonic lenses are given. Ultrasonic through-transmission and back-scattering images of different objects are presented and a quasi-three-dimensional display mode is introdued. A resolution of about 4 micron is demonstrated at 300 MHZ by the present ultrasonic microscope.

Erythrocytes↗