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PubMed1997

Ultrasonic separations in analytical biotechnology.

Cells in megahertz-frequency noncavitating ultrasonic standing waves concentrate at submillimetre distances and are, as large clumps, easily removed from suspension in flow or batch systems. An ultrasonic filter for perfusion hybridoma culture is now available. Results from small-volume prototype analytical-scale systems can inform the design of effective filter or batch-clarification systems for a wide range of cell sizes, concentrations and sample volumes. Large increases in the rates of aqueous biphasic separations and of the rates and sensitivities of analytical immunocoated particle-agglutination assays occur in standing waves. Ultrasonic manipulation is briefly compared with immunomagnetic and dielectrophoretic separations.

Biotechnology↗

PubMed1983

Wound healing of spleen ruptures by ultrasonic welding in animal experiments.

Violent ruptures of the spleen caused by accidents are regarded as an indication for necessary splenectomy. Experiences of modern ultrasonic surgery, e.g. in ultrasonic welding of bone fractures prompted us to experimentally investigate ultrasonic welding of spleen ruptures in dogs. We immediately obtained a safe closing of the ruptures with a durable scar and thus the method may give an alternative to splenectomy with saving of the organ.

Animals↗

PubMed1998

Progress in ultrasonic bioreactors for CELSS applications.

An important issue in Controlled Ecological Life Support Systems (CELSS) is the recycling of inedible crop residues to recover inorganic plant nutrients such as nitrates, phosphates, potassium and other macro- and micro-nutrients. In a closed system in space, such regeneration is vital to the long term viability of plant growth necessary for the food production and waste handling process. Chemical approaches to recycling such as incineration and wet oxidation are not compatible with low energy and environmentally friendly regeneration of such nutrients. Biological regeneration is more acceptable environmentally, but it is a very slow process and does not typically result in complete recovery of inorganic and organic nutrients. A new approach to biological regeneration is described here involving the combined use of special enzymatic catalysts and ultrasonic energy in a bioreactor system. This new system has the potential for rapid, efficient, environmentally friendly and complete conversion of crop wastes to inorganic plant nutrients and food recovery from cellulose materials. A series of experimental tests were carried out with a soybean crop residue meal substrate. Biochemical conversion rates were significantly expedited with the addition of enzymes and further enhanced through ultrasonic stimulation of these enzymes. The difference in conversion rates was particularly increased after the initial period of soluble organics conversion. The remaining cellulose substrate is much more difficult to biodegrade, and the ultrasonically-enhanced reaction was able to demonstrate a much higher rate of substrate conversion.

Biodegradation, Environmental↗

PubMed2002

Vibration characteristics of ultrasonic scalers assessed with scanning laser vibrometry.

OBJECTIVES: Scanning laser vibrometry is a non-invasive method of accurately measuring the vibratory characteristics of oscillating objects. The aim of this study was to observe, using a scanning laser vibrometer (SLV), the vibration patterns of dental ultrasonic scaler tips and to assess the effects of water flow rate and power setting on these patterns whilst operating the tips in an unloaded environment. METHODS: A 30kHz ultrasonic scaler (TFI-10, Dentsply) was fixed in position and a laser beam from the SLV was focused onto the tip. The laser, guided by a virtual measurement grid, was scanned over the oscillating tip surface. Scans were taken with the laser beam perpendicular to the long axis of the front face of the tip. RESULTS: Oscillation frequencies and the displacement amplitude at the unconstrained end of the tip were measured for various power/water settings. Vibration nodal positions were recorded for the various settings and were found to occur approximately 4mm from the free end of the tip. At low and medium power settings, tip displacement amplitude was reduced by increased water flow. At high power settings, combined with a high flow rate, the water leaves the body of the instrument as a jet. This left the tip relatively unconstrained, allowing it to oscillate at increased displacement amplitudes. CONCLUSIONS: This study shows that the SLV is able to accurately characterise the movement of oscillating ultrasonic scaler tips. The tips are affected by power setting and water flow rates.

Analysis of Variance↗

PubMed2000

Investigations into the use of an ultrasonic chisel to cut bone. Part 1: Forces applied by clinicians.

OBJECTIVES: To measure in vitro the direction and force of applied loads applied by clinicians when using both a conventional slow surgical handpiece (CH) and an ultrasonic chisel (USC) for cutting bone. STUDY DESIGN: Five clinicians were asked to cut bovine bone using either an USC or a CH. The bone was placed on a force measurement system that could measure both longitudinal and downward loads. The rate of cut was calculated over a fixed time-period and the depth of cut measured using a penetratometer. RESULTS: The magnitude of the longitudinal forces generated varied between 1.48 and 3.22 N (USC) and 0.04 and 4.56 N (CH). The CH had a pulling force directed towards the operator. Both instruments produced a similar range of downward forces although there was intra- and inter-operator variability. The rate of cut varied in a similar manner, however, the CH produced a significantly greater depth of cut (p < 0.05). CONCLUSIONS: The force measurement system demonstrated differences in the way clinicians used the USC and CH instruments to cut bone. Of the two cutting methods investigated, the rotary bur is more efficient than the ultrasonic chisel. An ultrasonic chisel does cut bone in a different manner from a conventional bur and clinicians may require training before using it clinically.

Analysis of Variance↗

PubMed2000

Investigations into the use of an ultrasonic chisel to cut bone. Part 2: Cutting ability.

OBJECTIVES: Ultrasound may offer a possible alternative to rotary instruments for removing bone. This study was undertaken to analyse in vitro the various factors that influence the cutting of bone by an ultrasonic chisel. STUDY DESIGN: A block of bovine femur was moved in a longitudinal direction under a stationary ultrasonic chisel. The force and depth of the cut was recorded for cutting rates of 28-112 mm/min and with increasing rake angles of 0 to +20 degrees. The pressure exerted by the chisel was recorded for different cutting rates. RESULTS: When the cutting rate increases there is a corresponding increase in the downward force which is followed by a decrease in the force at rates greater than 56 mm/min. The depth of the cut increases up to a rate of 56 mm/min after which it decreases. Both the longitudinal and downward forces do not change when the rake angle changes from 0 to +10 degrees. The downward force decreases when the rake angle increases from +10 to +20 degrees. CONCLUSIONS: The bone is cut slowly with the ultrasonic chisel, but this would assist in precision. Where such an instrument is used for cutting bone the clinicians should be aware that both low forces and cutting rates are required, and the instrument should be held at a low rake angle.

Animals↗

PubMed2002

Ultrasonic low-energy treatment: a novel approach to induce apoptosis in human leukemic cells.

OBJECTIVE: We evaluated the cytotoxic effect of ultrasonic irradiation at low energy on the viability of normal and leukemic cells and the potential mechanisms of action inducing this cytotoxicity. MATERIALS AND METHODS: Human leukemia cell lines (K562, HL-60, KG1a, and Nalm-6), primary leukemic cells, and normal mononuclear cells are treated by ultrasound at a frequency of 1.8 MHz during various exposure times (acoustical power of 7 mW/mL) and immediately tested for cell viability by the trypan blue exclusion assay. Apoptosis is evaluated by cell morphology, phosphatidylserine exposure, and DNA fragmentation. The mitochondrial potential, glutathione content, caspase-3 activation, PARP cleavage, and bcl-2/bax ratio are tested by flow cytometry. Cloning efficiency is evaluated by assays in methylcellulose. RESULTS: The technique we describe here, using minute amounts of energy and in the absence of any chemical synergy, specifically triggers apoptosis in leukemic cells while necrosis is significantly reduced. Ultrasonic treatment of 20 seconds' duration induces a series of successive phases showing the characteristic features of apoptosis: mitochondrial transmembrane potential disturbances, loss of phosphatidylserine asymmetry, morphological changes, and, finally, DNA fragmentation. In contrast to K562 cells, for which a significant reduction of cloning efficiency is observed, the growth of hematopoietic progenitors is totally unaffected. Ultrasound treatment is also associated with depletion of cellular glutathione content, suggesting a link with the oxidative stress. Moreover, the fact that active oxygen scavengers reduce ultrasonic-induced apoptosis suggests a sonochemical mechanism. CONCLUSION: The cell damage observed after exposure of leukemic cells to ultrasound is associated with the apoptotic process and may be a promising tool for a smooth, specific, and effective ex vivo purging of leukemic cells.

Apoptosis↗

PubMed1998

Enhancement of ultrasonically-induced hemolysis by perfluorocarbon-based compared to air-based echo-contrast agents.

Hemolysis induced by ultrasonic activation of various contrast-agent gas bodies was investigated. Canine whole blood, with high concentrations of the agents held in 1 mm thick chambers, was exposed in the nearfield of a 2.4-MHz ultrasound beam in a 37 degrees C water bath. Sterile phosphate buffered saline (PBS) served as a control agent without gas bodies. Albunex (Mallinckrodt Medical, St. Louis, MO) and Levovist (Schering AG, Berlin, Germany) represented the air-based contrast agents. The experimental agents FS069 (Optison, Molecular Biosystems Inc., San Diego, CA) and modified MRX-130 (ImaRx Pharmaceutical Corp., Tucson, AZ) represented perfluorocarbon-based contrast agents. No significant ultrasonically-induced hemolysis was detected for the PBS or Levovist suspensions. After 1 s continuous exposure, ultrasonically-induced hemolysis was significant for Albunex at 0.4 MPa or higher pressure amplitudes, for FS069 at 0.2 MPa and for modified MRX-130 at 0.4 MPa. Hemolysis found after pulsed exposure with 10 micros pulses and 1 ms pulse repetition period was significant for Albunex, FS069 and modified MRX-130 above thresholds of 1.1 MPa, 0.57 MPa and 1.6 MPa, respectively. FS069 led to more hemolysis after pulsed mode exposures of 1 s duration or longer than did Albunex. Reduced concentrations of gas bodies gave increased thresholds and reduced hemolysis. These results indicate that improvements in persistence of contrast agents, which increase their clinical utility, may also enhance the potential for cavitational bioeffects.

Air↗

PubMed1999

Ultrasonic enhancement of coated particle agglutination immunoassays: influence of particle density and compressibility.

The detection rate and sensitivity (analyte concentration limit) of coated particle agglutination immunoassays are increased in ultrasonic standing waves. The influence of particle volume, density and compressibility, properties that modify the ultrasonic radiation, and interaction forces the particles experience, on assay sensitivity with latex and silica particles in the range 0.25-1.0 microm is examined here. Streptavidin-coated 0.3-microm silica particles and 0.25-microm and 1.0-microm latex particles were examined for agglutination with biotinylated bovine serum albumin (bBSA) following exposure on axis in a 4.6-MHz radial standing wave. The lowest detection limit, 2 ng/mL bBSA, was achieved with the 0.3-microm silica. The detection limit decreased with increasing latex particle size. The limit of an ultrasound-enhanced agglutination immunoassay of rabbit antimouse immunoglobulin was 6-fold better with 1.0-microm coated silica than with equal-sized latex particles. Calculations show that the particle density-dependent ultrasonic interaction force dominates the particle compressibility force for the present case. The density-dependent force on silica, but not on latex particles, is shown to be comparable in magnitude to both the long-range van der Waal's attractive force and the electrostatic repulsion between the particles. This density-dependent force may explain the improved enhancement of analyte detection by coated silica compared with latex particles.

Agglutination Tests↗

PubMed1999

Magnitude of effect of reaction parameters on 2-chlorophenol decomposition by ultrasonic process.

In the present work, decomposition of o-chlorophenol (2-cp) was carried out using an ultrasonic process. The extent of 2-cp decomposition depends on several parameters such as ultrasound wave energy (ultrasonic amplitude), addition of hydrogen peroxide (H2O2), pH value (H+ concentration), ionic strength, and initial concentration of 2-cp. The experimental results showed that the decomposition of 2-cp was affected by the various reaction conditions. The profiles of 2-cp decomposition fitted well with the first-order kinetic equation. A linear relationship was obtained between the rate constants of 2-cp decomposition and the varying reaction parameters. The magnitude of effect of reaction parameters such as ultrasonic amplitude, H+ concentration, ionic strength, H2O2 and 2-cp initial concentration on 2-cp decomposition were 0.60, 0.48, 0.19, 0.09 and -0.06, respectively.

Biodegradation, Environmental↗

PubMed1989

Bimodal capsular bag phacoemulsification: a serial cutting and suction ultrasonic nuclear dissection technique.

A technique for emulsifying the lens nucleus within the capsular bag is presented. The circular continuous tear anterior capsulotomy (capsulorhexis) and nucleus hydrodissection, which are components of the technique, are identified. The concept of isolated cutting and suction as independent actions of the 45-degree ultrasonic phaco-emulsification tip is discussed. The two actions are achieved by alternating the orientation and action of the 45-degree ultrasonic tip in a multiple rotation nuclear dissection technique. The nucleus is collapsed and drawn centrally without aspirating nuclear material while the tip's aperture is near the lens capsule. This technique prevents the ultrasonic tip aperture from bursting through the peripheral nuclear shell and thus reduces the risk of capsular aspiration and vitreous loss.

Cataract Extraction↗

PubMed2001

Role of the ultrasonic surgical aspirator in gynecology.

As is true in neurosurgery and general surgery, the ultrasonic surgical aspirator is a powerful tool for the general gynecologist and gynecologic oncologist in assisting in the treatment and management of benign and malignant diseases. The physical properties of ultrasonic sound waves along with the composition of the tissues in question allow for safe, selective, and precise tissue resection. Although the ultrasonic surgical aspirator has had favorable results to date and future applications seem promising, the ultimate role of this device needs to be established with clinical trials.

Adenocarcinoma↗

PubMed1999

The safety and success rate of sputum induction using a low output ultrasonic nebuliser.

Induced sputum differential cell counts have been advocated as a method of non-invasively assessing airway inflammation in asthma and other airway diseases. Since sputum induction usually involves delivering hypertonic saline via a high output ultrasonic nebulizer there have been concerns about its safety in asthma. There are relatively little data on the effects of sputum induction in large numbers of patients. We have examined the success rate and effect of sputum induction on forced expiratory volume in 1 sec (FEV1) in 100 inductions performed on 79 patients using a low output nebulizer. Thirty-seven patients had asthma, 29 had miscellaneous conditions (mainly chronic cough) and 13 were subjects without respiratory symptoms. Sputum was induced 10 min after 200 micrograms of inhaled salbutamol by sequential 5-min inhalations of 3, 4 and 5% saline delivered via a Fisoneb ultrasonic nebulizer and FEV1 was measured after each inhalation. Sputum induction resulted in a sample suitable for analysis in 92% of asthmatics, 90% of those with miscellaneous conditions and 100% of normal subjects. The mean (SEM) maximum per cent fall in FEV1 was 5.4% (0.1), 4.3%, (1.0) and 2.6% (1.1) in subjects with asthma, miscellaneous conditions and in asymptomatic subjects respectively. Only 13 inductions resulted in a > 10% fall in FEV1, and only three of these resulted in a > 20% fall. The maximum per cent fall in FEV1 did not correlate with baseline FEV1 % predicted (r = -0.17), the log sputum eosinophil count (r = -0.12), or the methacholine PC20 (r = -0.14). We conclude that sputum induction using a relatively low output ultrasonic nebulizer with premedication with salbutamol is successful and safe in the majority of patients with asthma and other airway conditions.

Adolescent↗

PubMed1992

Gallstone lithotripsy: in vitro comparison of fragmentation with a tunable-dye laser and an ultrasonic wire.

Large bile duct stones require fragmentation prior to extraction through the papilla or through a percutaneous tract. This can be attempted with dissolution therapy, crushing baskets, or lithotripsy. Lithotripsy can be accomplished safely and effectively with tunable-dye laser energy delivered through a flexible, 1-F optical fiber under endoscopic or fluoroscopic guidance, but laser technology is very costly. A prototype, flexible ball-tipped wire coupled to an ultrasonic generator via a piezoelectric crystal has been developed for sonolysis of atheroma and thrombus in humans. The purpose of this experiment was to compare human gallstone fragmentation in vitro with a tunable-dye laser and this prototype wire to see if the less expensive ultrasound device might provide an alternative to costly laser technology. Gallstones from 17 patients were subjected to lithotripsy in a water bath with each device until completely fragmented or 60 seconds had elapsed. Neither device effectively fragmented cholesterol stones under these conditions. The ultrasonic wire completely fragmented 57% of bilirubinate stones in 60 seconds. The tunable-dye laser completely fragmented 100% of bilirubinate stones in less than 35 seconds (P = .04). Tunable-dye laser lithotripsy appears superior to the ultrasonic device for percutaneous treatment of bile duct stones.

Cholelithiasis↗

PubMed1993

Laparoscopic ablation of endometriosis using the cavitational ultrasonic surgical aspirator.

Surgical modalities such as electrosurgery and lasers have been used for many years to treat endometriosis. They are relatively unselective with wide scatter, however, leading to the potential for significant tissue damage and injury. As an alternative, a technique for performing laparoscopic excision and adhesiolysis using a cavitational ultrasonic surgical aspirator (CUSA) was developed and studied in 15 patients. Endometriosis was removed using a prototype titanium probe developed for a 10-mm laparoscopic port. The ultrasonic laparoscopic probe consisted of an acoustic vibrator, a coupling device, a removable tip, and a protective flue. Vibrations from the acoustic vibrator (magnetostrictive device) were conveyed to the operating tip through a coupling piece. The magnetostrictive device consisted of nickel alloy laminations 10.8 cm in length that transformed electrical energy into mechanical motion at the hollow titanium tip, vibrating at a frequency of 23 kHz. The excursion of the tip (amplitude setting) was arbitrarily set, with a fixed stroke of 200 microm in all cases to remove tissue with a 1- to 2-mm radius of the vibrating tip. The tip was tapered to obtain greater amplitude and ablation efficiency. When placed in contact with the endometriotic implants and adhesions, it destroyed and emulsified the cell membranes, which were irrigated and removed through a built-in suction tube. The resulting debris and irrigating fluid were removed through the hollow central portion of the probe. The vibrating tip was moved over the surgical site in a back-and-forth motion to allow continuous, controlled removal. Vessels larger than 0.5 mm in diameter, nerves, and fibrous tissue capsules rebounded with the ultrasonic vibration waves emitted by the CUSA, and thus were unimpaired by the procedure. The consistency of tissues was sensed accurately when the tip of the device was in contact with them. This tactile feedback was helpful in enabling the surgeon to differentiate target tissues. The future application of this instrument awaits the outcome of research.

Adult↗

PubMed1997

Comparison of conventional and ultrasonically assisted extractions of pharmaceutically active compounds from Salvia officinalis.

Conventional as well as ultrasonically assisted extractions of biologically active compounds from Salvia officinalis using 65% ethanol have been studied. Cineole, Thujone and Borneol were used as standards for the GLC-MS evaluation of the extracts. The effect of temperature, stirring and mode of sonication (ultrasonic bath or horn system) have been studied. The results indicate that ultrasonically assisted extraction with mechanical stirring at room temperature in a period of 12 h produces a substantial improvement over conventional methodology.

Bicyclic Monoterpenes↗

PubMed2001

Ultrasonic frequencies calculated for the q[100] mode in the first-order, tricritical and the second-order phase transitions of NH4Cl.

This study correlates the volume changes to the ultrasonic frequencies of the q[100] mode of NH4Cl for the first-order, tricritical and the second-order phase transitions in this crystal. Using these correlations we were able to calculate the ultrasonic frequencies of this mode at the pressures of 0, 0.6 and 1.1 kbar (first-order), 1.6 kbar (tricritical) and 2.15 kbar (second-order) by means of the volume change data from the literature. Our calculated frequencies are in good agreement with the observed data for the phase region below the critical temperature T(C) for the first-order, tricritical and the second-order phase transitions in NH4Cl. Above T(C) our calculated frequencies do not agree satisfactorily for the q[100] mode and it is incapable of explaining the observed behaviour of NH4Cl. Our method of calculating the ultrasonic frequencies is presented.

Ammonium Chloride↗

PubMed2004

[Video-assisted thoracoscopic sympathectomy for the treatment of facial flushing: ultrasonic scalpel versus diathermy].

OBJECTIVE: To evaluate the advantages of the ultrasonic scalpel compared to electrocoagulation in patients undergoing video-assisted thoracoscopic sympatholysis or sympathectomy for uncontrolled facial blushing. METHODS: Two hundred bilateral video-assisted thoracoscopic procedures to interrupt transmission in the thoracic sympathetic nerve were performed in 100 patients with incapacitating facial blushing. In 2 cases, the video-assisted approach was chosen because of pleural symphysis. The mean age of patients was 34 years (range: 15 to 67). The sympathetic chain was interrupted from the lower portion of the first thoracic ganglion through the third. RESULTS: All patients were discharged within 24 hours with the exception of one on whom an emergency thoracotomy had been performed. No complications were reported in the group in which a harmonic scalpel was used. One case of temporary Horner syndrome (4 months) and 3 cases of persistent chest pain (more than 2 weeks) were reported in the diathermy group. There were 9 cases of partial and asymptomatic pneumothorax that resolved without treatment or prolonged hospital stays. CONCLUSION: Dissection of the sympathetic nerve is accomplished more reliably and with better visualization with the ultrasonic scalpel. Peripheral lesions in lung parenchyma and adjacent tissues (intercostal vessels and nerves) are avoided, as is Horner syndrome, which can be caused by dispersion of heat. Use of the ultrasonic scalpel would also lead to a lower incidence of postoperative neuralgia.

Adolescent↗