Evaluation of a biosurfactant extract obtained from corn for dermal application.

At present, there is an increasing demand to improve the sustainability of surface-active compounds in dermal formulations. Biosurfactants, which are derived from living cells, are considered to be more environmentally friendly than synthetic surfactants. Thus, the use of biosurfactants is a promising strategy for the formulation of more environmentally friendly and sustainable dermal products. In this work, a biosurfactant extract (BS) obtained from corn wet-milling industry was studied for its potential use in dermal formulations. The corn derived BS possesses good surface-active properties and was found to be a suitable co-stabilizer for nanoemulsions and nanocrystals for dermal application. It also possesses antioxidative and skin protective properties and was also able to increase the dermal penetration efficacy for lipophilic actives. In dermal formulations the BS can therefore be used as co-stabilizer with antioxidative and penetration enhancing properties at the same time.

Comparison of normal and diseased pulmonary artery morphology by intravascular ultrasound and histological examination.

The study was performed to determine the morphological characteristics of normal and diseased pulmonary arteries by ultrasound (intravascular ultrasound, IVUS) and histology. Forty-nine cadaver segments of pulmonary arteries from 16 postmortem patients were imaged in vitro by IVUS and compared to matched histological sections. The pulmonary vasculature of 11 patients with pulmonary hypertension was investigated in vivo by IVUS. In the in vitro study, 34 of a total of 143 histological sections of the segmental pulmonary arteries showed fibrotic wall components; the remaining 109 sections had regular components. Imaged by IVUS, the wall of the regular and fibrotic arteries revealed a single layer histologically, representing the intima, media, adventitia and connective tissue. Adjacent lung tissue could be detected by IVUS and was confirmed by the histological section. In three patients with a history of chronic embolic pulmonary hypertension, IVUS revealed thrombi or a double vessel wall layer. Histologically, the material extracted after pulmonary thromboendarterectomy in two patients showed wall-adherent thrombus features of early organization. In all other patients only a single wall layer was seen. The vessel walls (intima, media, adventitia and connective tissue) of regular and slightly fibrosed pulmonary arteries show only a single layer. Wall-adherent organized thrombi in chronic embolic pulmonary hypertension can be detected by IVUS as a second inner vessel layer. Thus IVUS may represent an additional tool for detecting chronic embolic pulmonary hypertension when the results of pulmonary angiography or computed tomography are not definite.

A new thrombectomy catheter device (AngioJet) for the disruption of thrombi: An in vitro study.

In this study we examined a new thrombectomy catheter device. Different kinds of in vitro generated thrombi and cadaver thrombi were disrupted in test tubes. The mean disruption rate (and disruption time for 1 g of thrombus) was 225 +/- 65 mg/sec (5 +/- 2 sec) for whole-blood, 117 +/- 60 mg/sec (12 +/- 9 sec) for fibrin, 41 +/- 18 mg/sec (30 +/- 18 sec) for mixed, 70 +/- 42 mg/sec (17 +/- 5 sec) for unorganized, 45 +/- 8 mg/sec (22 +/- 4 sec) for partly, and 5 +/- 1 mg/sec (216 +/- 29 sec) for completely organized cadaver thrombi (P < 0.05). More than 99% of fragmented particles of whole-blood thrombi were 0-12 microm in diameter. The particle size of fibrin, mixed, and cadaver thrombi was similar, with 25%-40% of particles between 0-12 microm, 55%-71% >12-24 microm, and 2%-7% >24 microm. The device may be effectively used in the therapy of massive pulmonary embolism or acute peripheral and coronary artery syndromes when medical thrombolysis is contraindicated and organization of thrombus is absent. Further studies need to be performed to investigate the potential effects of particle microembolization. Cathet. Cardiovasc. Intervent. 47:381-389, 1999.

In vitro examination of the coronary artery wall after balloon angioplasty using intracoronary ultrasound.

After autopsy 12 human coronary arteries were investigated by intracoronary ultrasound in order to measure the vessel wall dimensions and to detect damage on the vessel wall architecture after balloon angioplasty. Histology revealed artherosclerosis in 11/12 arteries. A total of 41 representative coronary segments were selected for further off-line ultrasound and histological analysis. Intracoronary ultrasound and histological measurements of the vessel wall thickness after balloon dilatation demonstrated a good correlation between the maximum thickness of the intima (histology 0.62 mm vs. intracoronary ultrasound 0.65 mm, r = 0.87) and the intima-media complex (0.80 mm vs. 0.83 mm, r = 0.87), in contrast to a weak one between the minimum thickness (r = 0.46 and r = 0.37). A total of 21 cases of damage occurred during angioplasty; intracoronary ultrasound detected 17. Further analysis showed that it imaged 10 of 11 cases of damage involving more than 30 degrees of the vessel circumference and 7 of 10 cases of damage involving less than 30 degrees of the vessel circumference. After balloon angioplasty of diseased coronary arteries, intracoronary ultrasound is therefore reliable in measuring the maximum wall thickness and in imaging damage involving more than 30 degrees of the vessel wall circumference.

Transthoracic three-dimensional echocardiographic volumetry of distorted left ventricles using rotational scanning.

The purpose of this study was to evaluate the relation of transthoracic three- and two-dimensional echocardiographic left ventricular volumetry to cineventriculographic volumetry. Twenty-five patients with distorted left ventricles were included in the study. To demonstrate the impact of acquiring data by rotational scanning, we performed three- and two-dimensional echocardiography in 36 latex ventricles with data acquisition in different areas of the ultrasound sectors. Interobserver and intraobserver variability were calculated to test for reproducibility. The three-dimensional imaging system consisted of a rotation motor device, a transthoracic 2.5 MHz transducer, a conventional ultrasound unit, and a work-station (TomTec) which provides data acquisition, post-processing, and two- or three-dimensional visualization of digitized data. The transducer moved automatically at 2-degree increments with data acquisition at each tomographic level. The mean investigation time for three-dimensional echocardiography was 21 +/- 6 minutes. In the central near field of the transducer, differences from true volumes in latex ventricles were remarkably smaller for three-dimensional compared with two-dimensional echocardiography (root mean square percent error: three-dimensional echocardiography = 5.3% versus two-dimensional echocardiography = 14.6%). In three-dimensional echocardiography, there was considerable overestimation of volumes in the lateral far field (root mean square percent error = 13.2%) of the ultrasound sector. Differences between two-dimensional echocardiographic human left ventricular volumes and cineventriculography increased with larger volumes. In three-dimensional echocardiography the differences remained constant. Interobserver and intraobserver variability is reduced nearly twofold by three-dimensional echocardiography. Three-dimensional echocardiographic volumetry provides fewer discrepancies to cineventriculography and lesser variability than two-dimensional echocardiography. With the use of rotational scanning, the ventricle has to be positioned in the central near field of the transducer.

Importance of calibration for diameter and area determination by intravascular ultrasound.

BACKGROUND: Intravascular ultrasound (IVUS) permits quantitative assessment of the lumen diameter and area of coronary arteries. The experimental study was performed to evaluate the accuracy of diameter and area measurements. METHODS AND RESULTS: Lumen quantitation (lumen diameter D and cross-sectional area A) in lucite tubes (lumen diameter 2.5 to 5.7 mm, Plexiglas) was performed using a mechanical IVUS system (HP console, 3.5 F catheter, Boston Scientific, 30 MHz). The influence of fluid type (blood, water and saline solution), fluid temperature (20 degrees C/37 degrees C), catheter to catheter variation, gain setting and ultrasound frequency (12, 20 and 30 MHz) was determined. In blood at 20 degrees C there was a constant deviation of the measured diameter from the true luminal diameter of -0.29 +/- -0.04 mm (p < 0.06). In water and saline solution at 20 degrees C the mean deviation from true diameter was -0.21 +/- -0.06 mm (p < 0.06). At 37 degrees C, the deviation in blood was greater than at 20 degrees (-0.34 +/- -0.02 mm) which is > 10% in a 3 mm tube (p < 0.06). Three of the ten catheters tested in water at 20 degrees C underestimated true diameter by more than -0.3 mm. The deviation from true diameter (5 mm tube) with varying gain settings was -0.14 mm to -0.23 mm compared to -0.19 mm at standard settings (p > 0.288). At 12 MHz diameter measured was over-estimated. The error in absolute area estimation increased with increasing diameter tested in blood at 37 degrees C (-1.21 to -2.72 mm2), whereas the relative error ([Measured Area-True Area]/True Area x 100 [%]) was more striking at smaller diameters (up to -25% in the 2.5 mm tube). CONCLUSION: Luminal diameters and areas are underestimated by this particular IVUS system. When IVUS imaging and measurements are made during coronary interventions this error should be taken into account with regard to appropriate sizing of the device and the assessment of the postprocedure result. Because systematic errors might also occur in other IVUS system (not tested in this study), it is advisable to ensure that each system is validated prior to clinical use, especially when exact measurements are required.

Intravascular ultrasound detected classification of coronary lesions as a predictor of dissections after balloon angioplasty.

Dissection after balloon angioplasty of coronary arteries may give rise to an unfavourable early outcome. Compared with coronary angiography, intravascular ultrasound (IVUS) allows more detailed characterisation of dissections. We investigated the incidence and type of dissections after balloon angioplasty in calcified coronary lesions. IVUS was performed in 43 patients with 48 lesions before and after percutaneous balloon angioplasty. Significant calcification was defined as an arc of more than 90 degrees with typical acoustic shadowing. Dissections were classified as type A when the media was not involved by the dissection and as type B when media involvement had occurred. In the group with significant calcification dissection was observed in 79% of the cases vs 38% in the control group (p < 0.03). Type B dissection was present in 71% of the dissections in the calcified lesions vs. 15% in the control group (p < 0.02). The balloon diameter and the ratio of balloon area to vessel area was not different in both groups but the required pressure for the first complete balloon inflation was significantly greater in the group with calcified lesions (9.46 +/- 3.6 atm vs. 6.65 +/- 2.6 atm; p < 0.001). Thus balloon angioplasty in calcified coronary lesions is more likely to lead to dissection with frequency involve the media.

Differences in the morphology of unstable and stable coronary lesions and their impact on the mechanisms of angioplasty. An in vivo study with intravascular ultrasound.

The aim of this study was to compare the morphology of stable and unstable coronary lesions using intravascular ultrasound in patients undergoing coronary balloon angioplasty and to determine whether lesion morphology had any influence on the mechanism of balloon angioplasty. Thirty three (15 stable and 18 unstable) patients undergoing single lesion percutaneous transluminal coronary angioplasty were studied with intravascular ultrasound before and after intervention. All examinations, recorded on S-VHS video tape, were studied off-line and matched sites from the point of minimum lumen area after the procedure and the corresponding site prior to intervention were compared. The morphology of lesions before intervention was noted and the mechanisms of angioplasty (vessel stretch, lesion remodelling and lesion tears) were determined by comparing pre- and post-interventional morphology and dimensions. The only significant morphological difference between stable and unstable lesions was the presence of a demarcated inner layer in unstable lesions, delimited by a fine circumferential line. This pattern was noted in 77% (14/18) of unstable lesions and in 7% (1/15) of stable lesions (P < 0.01). Unstable lesions tended to have more echolucent zones than stable lesions (72% (13/18) vs 46% (7/15), P = 0.13). The mechanisms of angioplasty were also found to differ. Whereas lesion remodelling (or 'compression') was seen in 77% (14/18) of unstable lesions, it occurred in only 13% (2/15) of stable lesions and mean lesion cross-sectional area reduction was greater in unstable lesions, - 14.8 +/- 8.3% (2.1 +/- 1.3 mm2) compared to stable lesions, - 4.1 +/- 8.4% (0.42 +/- 0.9 mm2), P < 0.01. In contrast, vessel stretch was seen more frequently in stable lesions (73%, 11/15) compared to unstable lesions (22%, 4/18) P < 0.01 and the mean increase in vessel cross-sectional area was + 13.5 +/- 6.8 (1.6 +/- 0.9 mm2) in stable lesions compared to + 5.5 +/- 5.6% (0.8 +/- 0.9 mm2) in unstable lesions, P < 0.01. Lesion tear was present to a similar degree in both groups of patients. In this observational study we found a set of echographic markers that distinguished unstable lesions. The mechanisms of angioplasty differed between stable and unstable angina, with greater lesion remodelling seen in unstable lesions and vessel stretch in stable lesions. Taken together, these findings suggest that the markers we describe may be echographic indicators of mural thrombus.

[Experimental ultrasound angioplasty: in vitro resolution of thrombi]. / Experimentelle Ultraschallangioplastie: In-vitro-Auflösung von Thromben.

A new ultrasonic angioplasty ablation catheter connected to a 19.5 kHz. 25 W transducer was tested in vitro for its ability to disrupt 12-h. 24-h, and 5-day-old whole blood thrombi (n = 45.697 mg +/- 223 mg) and fibrin thrombi (n = 45.338 mg +/- 133 mg), as well as 5-day-old cadaver thrombi (n = 8.270 mg +/- 71 mg) within 10 min. Five of each age were used as control thrombi in which the catheter was moved back and forth without ultrasound emission. The size of ablated thrombus particles was measured by a laser device. The power output at the end of the catheter was assessed calorimetrically. The loss of weight of whole blood thrombi was between 429 (74%) and 524 mg (91%) (p < 0.01, whole blood thrombi vs. control thrombi) and between 302 (85%) and 314 mg (95%) (p < 0.05) for fibrin thrombi, respectively. Thrombus age did not prove to be a highly significant influencing factor. The disruption rate for whole blood thrombi was 0.75 to 1.05 mg/s and for fibrin thrombi 0.69 to 0.7 mg/s. It was only 0.09 mg/s for the cadaver thrombi. 93% of all particles ablated from whole blood thrombus ranged between 0-5 micron, less than 0.2% between 30-150 microns. For fibrin thrombi 69% of all particles were < 10 microns (25% between 10-20 microns). Only 0.02% ranged between 300-600 microns, which was similar for cadaver thrombi. The mean measured power output at the catheter tip was 5.9 W compared to the power output of 25 W at the ultrasound generator.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous ultrasonic angioplasty: initial results of an in-vitro study on normal and atherosclerotic human vessel segments.

The aim of the present study was to assess the efficacy and safety of a new ultrasound catheter system in vitro before employing it in humans. Ultrasound energy was applied to 141 normal and atherosclerotic human vessel segments, obtained at autopsy. Macroscopical and histological examination of the treated vessel segments revealed that ultrasound energy is atraumatic to the normal vessel wall. In atherosclerotic vessel segments, there was macroscopically significant reduction in the size of plaques. In 7/10 completely occluded femoral arterial segments, recanalization could be achieved. The resulting lumen approximated the diameter of the wire probe. Therefore, ultrasound energy is an appealing form of energy for recanalization of completely obstructed atherosclerotic vessels and for disintegration of atherosclerotic plaques. Clinically, ultrasonic angioplasty may become an adjunctive modality to balloon angioplasty.

Analysis of high-frequency rotational angioplasty-induced echo contrast.

During high-frequency rotational angioplasty (HFRA), myocardial contrast enhancement (echo contrast) was observed by means of two-dimensional echocardiography. In order to evaluate the echo contrast produced by HFRA, an in vitro experimental model was built using a cylinder with the HFRA catheter scanned in a water bath. The cylinder was filled with blood, mineral water, and distilled water. With a 2.5-MHz transducer, echograms were recorded and analyzed by video intensitometer, and the maximum intensity IUmax and persistence time P were calculated. Rotation frequencies of 20,000-200,000 rpm with 2.0--mm burrs and times of 10 s were tested. In another model, hyperbaric conditions for the same media were produced. The influence of debris from arterioscleroic plaque and of hematocrit on echo contrast intensity were also analyzed. The effect of HFRA on hemolysis (LDH, free hemoglobin) within 10 s and temperature were also measured. The contrast effect was transient, depending on the rotation frequency. In blood, it appeared at 20,000 rpm (IUmax at 200,000 rpm: 237 IU), in mineral water at 40,000 rpm (IUmax 165 IU), and in distilled water at 80,000 rpm (IUmax 72 IU). Persistence time was measured up to about a half-minute. Echo contrast production was reduced at 0.5 bar and fully suppressed at 2.5 bar. Debris increased contrast intensity from about 219 IU to 225 IU (at 160,000 rpm). In blood IUmax decreased from 227 IU to 97 IU by lowering the hematocrit from 44.2% to 3.6%.(ABSTRACT TRUNCATED AT 250 WORDS)