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At least 955 records · Page 53Linked to original sources
PubMed1980

Comparison of multigated radionuclide angiography with ultrasonic sonomicrometry over a wide range of ventricular function in the conscious dog.

This study compared the noninvasive assessment of left ventricular function with radionuclide angiography with that obtained with ultrasonic sonomicrometry. Left ventricular ejection fraction and rate of ventricular ejection (dV/dt) were measured with both techniques over a wide range of ventricular function. Six dogs were prepared with epicardial crystals across the major and minor axes of the left ventricle, paired transmural wall thickness crystals and a left ventricular catheter. The animals were studied while awake after they had recovered from operation. Left ventricular volume was calculated from the ultrasonic sonomicrometric dimension measurements and the equation for a prolate ellipsoid; dV/dt was calculated from the stroke volume and ejection time. Radionuclide angiograms were performed using technetium-99m--labeled red blood cells and an Anger camera with a converging collimator interfaced to a computer programmed for multigated acquisition. A wide range of ventricular function was produced with sequential infusion of isoproterenol, propranolol, phenylephrine and sodium thiamylal. Ejection fraction and dV/dt were measured simultaneously during each intervention using the time-activity curves of the multigated radionuclide angiogram and ultrasonic sonomicrometric dimensions. Regression analyses demonstrated a close correlation between the simultaneous measurements of ejection fraction (r values ranged from 0.95 to 0.99) and dV/dt (r values ranged from 0.87 to 0.99). These data indicate that noninvasive multigated radionuclide angiography accurately assesses changes in ejection fraction and dV/dt over a wide range of ventricular function.

Animals↗
PubMed1980

Ultrasonic imaging of the carotid arterial system.

The ability of a B-mode, real-time, high frequency ultrasonic imager to diagnose carotid arterial disease was evaluated in 81 carotid arteries. The imager was relatively sensitive in detecting the presence of significant stenosis but was relatively insensitive in its ability to quantitate the degree of stenosis. The imager was unable to detect the presence of ulcerations. The oculoplethysmograph had a greater sensitivity, specificity and accuracy than the ultrasonic imager in diagnosing carotid arterial stenosis in the same group of patients. Ultrasonic imaging appears to be useful as a screening test of cerebrovascular disease when used in combination with the oculoplethysmographic test.

Arterial Occlusive Diseases↗
PubMed1982

Operative ultrasonic features of insulinomas.

The technique of operative pancreaticosonography is described as a method of localizing occult insulinomas. The specific ultrasonic features of two small but palpable insulinomas are compared with those of other small lesions in the pancreas. Insulinomas are ultrasonically hypoechoeic and well-defined, with smooth borders, they deform but do not infiltrate surrounding structures, and they cause some dilatation of the secondary pancreatic ducts. Real-time, high resolution, intraoperative ultrasonic pancreatography is suggested as an adjunct to assist in the localization of insulinomas at surgery.

Adenoma, Islet Cell↗
PubMed1991

Ultrasonic decalcification of the aortic annulus during aortic valve replacement.

Aortic valve replacement for calcifica aortic stenosis requires meticulous debridement of the aortic annulus to effect optimal valve seating. Since 1987, we have used ultrasonic energy to debride the aortic annulus during aortic valve replacement in 56 patients. In our experience, ultrasonic debridement of the annulus is superior to traditional methods of debridement, affords improved seating of the valve, and may allow placement of a larger valve. Our follow-up ranges from 2 to 32 months (mean follow-up, 13 +/- 9 months) with 0% incidence of paravalvular leak or valve failure. We advocate the use of ultrasonic debridement as an adjunctive tool in aortic valve replacement.

Adult↗
PubMed1987

Ultrasonic studies of proton-transfer reactions at the catalytic site of alpha-chymotrypsin.

Ultrasonic relaxation measurements for alpha-chymotrypsin in phosphate, sulfite and arsenate buffers exhibit a high peak of absorption at neutral pH. The analysis is based on: comparison of the relaxation measurements for the enzyme and for the zymogen and inhibited enzyme; X-ray and neutron diffraction data, and high-resolution NMR data. The ultrasonic relaxation is shown to result mainly from a proton-transfer reaction that involves the histidine at the catalytic site (His-57). The question is raised of whether the enhanced ultrasonic effect observed in the enzyme is indicative of a property that plays a part in the catalytic activity.

Binding Sites↗
PubMed1993

Rapid agglutination testing in an ultrasonic standing wave.

The time taken to perform diagnostic agglutination tests can be significantly reduced by applying an ultrasonic standing wave field to a droplet of reactants held in a capillary tube. Avian erythrocytes, bacteria and latex particles from commercially available test kits were agglutinated in 15 s, 5 min, and 1 min respectively. These times compare favourably with the times of 30 min, 4 h, and 8 min required for agglutination by the methods prescribed for the respective kits. No loss in sensitivity or specificity was observed with the ultrasonic method. A multi-test procedure is also described whereby a series of five droplets loaded in a single capillary can be tested in less than 4 min by drawing the capillary along the axis of the ultrasonic field of a ring transducer.

Agglutination↗
PubMed1986

Ultrasonic vocalization in rat pups: effects of early postnatal exposure to haloperidol.

The effects of prolonged postnatal administration of haloperidol (H) on ultrasonic vocalization elicited by the removal of rat pups from their nest were investigated. The results show that the number of ultrasonic calls was significantly reduced by H exposure from the 8th until the 14th day after birth. Conversely, this neuroleptic significantly increased the duration of ultrasound from the 4th up to the 16th day of age. Moreover, changes in the frequency of calls were produced by early postnatal treatment with H. These alterations could be due to an impaired functional maturation of the dopaminergic system produced by neonatal exposure to H. Furthermore, the present data suggest that ultrasonic vocalization may be considered as an early sensitive indicator of subtle changes elicited by the postnatal treatment with a dopamine receptor blocking agent at dose levels below those associated with overt signs of neurotoxicity.

Animals↗
PubMed1992

Ultrasonic vocalization as an indicator of emotional state during active avoidance learning in rats.

Adult male rats subjected to a two-way avoidance task emitted ultrasonic vocalizations (20-30 kHz) both during the presentation of the conditioned stimulus and the intertrial interval. The rate of ultrasonic calling decreased during the 75-trial session indicating that acquisition of the conditioned avoidance response (CAR) was inversely correlated with the rate of vocalization. The rate of acquisition of the CAR was most rapid in those rats that did not emit any vocalization during learning. These data suggest that ultrasonic calling during stressful situations may be sensitive indicator of underlying emotional states that interfere with the acquisition of a complex task.

Animals↗
PubMed1975

The healing of surgical defects in alveolar bone produced with ultrasonic instrumentation, chisel, and rotary bur.

A histologic comparison of the effects of an ultrasonic instrument, a low-speed rotary cutting bur, and a surgical chisel, all used with water coolant, on the rate of healing of dog alveolar bone was made. After reflection of a mucoperiosteal flap, each instrument was used to produce a 3 by 3 by 2 mm. defect in buccal alveolar bone, 3 mm. apical to the alveolar crest and directly overlying the root structure of the right premolar teeth. Dogs were killed immediately following flap replacement with sutures and 3, 7, 14, 28, 56, and 90 days later. Histologic examination of the surgical areas revealed that the bur produced the smoothest surface. At day 3, specimens prepared with the chisel and the ultrasonic instrument exhibited areas of cellular organization along surfaces with the defect and the formation of osteoid in adjacent marrow spaces. At day 7, osteoblastic activity was most pronounced in specimens prepared with the chisel and least in those prepared with the bur. The subsequent rate of healing in later periods appeared histologically to be the best with the use of the chisel, followed closely by the use of the ultrasonic instrument, and the slowest with the bur, the order of which is consistent with the over-all microscopic evaluation of the effect of the three instruments.

Alveolar Process↗
PubMed1987

Bacteriologic evaluation of ultrasonic root canal instrumentation.

The antibacterial effect of ultrasonic instrumentation in the treatment of infected root canals was clinically evaluated. Sodium hypochlorite solution (0.5%) was used as an irrigant, but no antibacterial intracanal dressing was used between the appointments. The ultrasonic technique eliminated the bacteria from the canals more efficiently than hand instrumentation alone. Even though ultrasonication definitely improves the procedure of root canal disinfection, the use of an antibacterial dressing between appointments is necessary to achieve as complete a reduction in bacterial levels as possible.

Bacteria↗
PubMed1982

Sagittal knife cuts in the near and far lateral preoptic area-hypothalamus reduce ultrasonic vocalizations in female hamsters.

Although it has been reported that lesions of the medial preoptic area reduce ultrasonic vocalizations in female hamsters, the neural connections of this area important for ultrasound production have not been investigated. We, therefore, tested vocalizations in female hamsters following sagittal cuts along the medial preoptic area-medial anterior hypothalamic continuum (MPOA-MAH) at either the medial (Near Lateral or NL cuts) or lateral (Far Lateral or FL cuts) border of the medial forebrain bundle (MFB). Bilateral NL and FL cuts did not affect spontaneously occurring vocalizations or vocalizations occurring during contact with males, but were equally effective in substantially blocking increases in vocalizations following exposure to males. Another group of animals with a unilateral NL cut and a contralateral FL cut showed a vocalization deficit comparable to that in NL and FL groups, suggesting that NL and FL cuts severed a common pathway important for ultrasonic calling. These results indicate that the lateral connections of the MPOA-MAH are critical for ultrasonic vocalizations. Alternatively, a ventral pathway from the medial amygdala to the bed nucleus of the stria terminalis, one which crosses the plane of both NL and FL cuts, is discussed in relation to the deficits observed.

Amygdala↗
PubMed1986

Ultrasonic vocalizations and aggressive behavior in male rats.

The aim of the present study was to know whether 22-28-kHz vocalizations have any communicatory role in the regulation of aggressive behavior in male rats of the Wistar strain. In pairs of intact rats 22-28-kHz vocalizations showed a positive correlation with the extent of aggressive behavior. The pattern of aggressive behavior during ultrasonic vocalizations was different from that just before and just after the vocalizations. However, surgically deafened rats were less active in aggressive behavior and more active in ambulatory activity in the open field than the controls. Muted rats were not different from the controls in both aggressive behavior and ambulatory activity. The present result that the deprivation of ultrasonic signals failed to increase aggressive behavior does not support the classical hypothesis that ultrasonic vocalizations inhibit the initiation of aggressive behavior. It is concluded that ultrasounds emitted during aggressive encounters may have little communicative value in male rats.

Aggression↗
PubMed1990

Startle-inducing acoustic stimuli evoke ultrasonic vocalization in the rat.

The present study demonstrates that acoustic stimuli which induce a startle response (ASR) also evoke ultrasonic vocalization in the rat. Sound recordings were done on three consecutive days of testing during sessions of 20 acoustic stimuli each and on the following day for three minutes following 5 acoustic stimuli (nonstimulus condition). Startle-inducing stimuli evoked continuous ultrasonic calling which was maintained throughout testing. Immediately following each acoustic stimulus, however, vocalization was interrupted by a period of silence (gap). The mean duration of sounds was reduced and the interpulse interval tended to increase during acoustic stimulation as compared to the nonstimulus condition. It is concluded that startle-eliciting stimuli induce a state of fear in the rat and that the acoustic-startle-elicited ultrasonic vocalization may provide a novel model in the study of anxiety.

Animals↗
PubMed1976

A comparison of heat production and cavitational intensity in several ultrasonic cell disruptors.

High power ultrasonic equipment is now commonplace in biological, chemical and pharmaceutical laboratories. These devices are being used for a variety of purposes including emulsification, dispersion, extraction and cell disruption. The average researcher has little basis for comparing the relative energy output of various ultrasonic probes at different power settings and he has neither the interest nor the time to determine their relative heat production. This research was designed to prepare a series of relative power indices and temperature profiles for several ultrasonic cell disruptors. Even though there are variations among equipment bearing the same model number it was considered worthwhile to make available relative cavitational and temperature data.

Sonication↗
PubMed1984

Ultrasonic and electrohydraulic lithotripsy of ureteral calculi.

Ultrasonic lithotripsy of ureteral calculi has been accomplished using a fine flexible ultrasonic probe under direct visual control through a 9-F rigid ureteroscope. Electrohydraulic ureterolithotripsy was performed by passing a 5-F catheter-electrode cystoscopically under fluoroscopic control. Case reports are presented. It is concluded that ultrasonic ureterolithotripsy, using the technique described, is a feasible and safe method. Although stone fragmentation by electrohydraulic ureterolithotripsy is possible, the danger of ureteral injury and urinary extravasation is appreciable.

Adult↗
PubMed1991

Bladder outlet obstruction treated with transurethral ultrasonic aspiration. One-year follow-up on 59 patients.

Fifty-nine males with bladder outlet obstruction were treated with transurethral ultrasonic aspiration of the prostate. Utilizing a 26.5F urethral sheath, surgery was accomplished with a 10F, 0-700-micron-vibration-level ultrasonic tip with an excursion rate of 39 kHz. Complete removal of the adenoma was accomplished followed by transurethral electrocautery biopsies of both lateral lobes to compare pathologic specimens. One year follow-up revealed satisfactory voiding patterns in 57 of 59 men (96%). Bladder neck contractures developed in 2 men. Pathologic comparisons showed 100 percent correlation between aspirated and TUR specimens (56 BPH, 3 adenocarcinoma). Forty-seven men were active sexually preoperatively (6 with inflatable penile prostheses). Post ultrasonic aspiration, 46 men had erectile function similar to preoperative levels with 1 patient suffering erectile dysfunction. Forty men (85%) had antegrade ejaculation while 7 (15%) experienced retrograde or retarded ejaculation. No patients were incontinent.

Adenocarcinoma↗
PubMed1992

Morphine attenuates antipredator ultrasonic vocalizations in mixed-sex rat colonies.

Mixed-sex groups of laboratory rats living in a visible burrow system (VBS) emit 18-27 kHz ultrasound and retreat to the burrow when a cat is placed in the open area of the VBS. The total duration of ultrasonic vocalizations was reliably reduced by pretreatment with 5 mg/kg morphine. In a subsequent study using male-female colony pairs, presentation of a cat to individual rats in the absence of their colony mate indicated significant gender differences in base frequency, degree of emission, and characteristics of pulses elicited. Specifically, females showed a greater number and duration of vocalizations, of higher frequency (kHz), and with shorter individual pulse durations than males. In the same study, morphine (5 mg/kg) produced a general decrease in the level of ultrasonic emissions in both sexes, reduced the mean base frequency (kHz), and increased the mean duration of individual pulses. These data suggest that endogenous opioid mechanisms may be involved in the mediation of ultrasonic vocalization in response to a predator, and are discussed with reference to known involvement of such systems in defensive responding.

Animals↗