Genesis of ultrasonic microbubbles: a quick historical overview

Microbubbles were the subject of numerous experiments and theoretical analysis over the past 100 years. Linked with the discovery and evolution of ultrasound, they were considered to be excellent echoenhancers. From the theories on acoustic waves in antiquity and the discovery of ultrasound, to the genesis of microbubbles around 1968, in our paper we trace the magnificent story of these "magical" bubbles.     

Analysis of contrast-enhanced intravascular ultrasound images for the assessment of coronary plaque neoangiogenesis: another step closer to the identification of the vulnerable plaque

Atherosclerotic cardiovascular disease (CVD), primarily manifested as heart attacks and strokes, remains the main cause of death in the developed countries and is rapidly increasing in the developing world. Early detection and aggressive treatment of hidden (asymptomatic) atherosclerotic plaques that cause heart attack or stroke are most needed. However, existing clinical tools are not sufficient to address this need. Intravascular ultrasound (IVUS) is a catheter-based medical imaging tool that is capable of providing cross-sectional images of arteries. It is by far the most powerful clinical tool available for characterization of atherosclerotic plaques. However, existing IVUS is unable to detect plaque inflammation which is a key factor in complications of atherosclerotic plaques. Contrast enhanced IVUS (CE-IVUS) for detection of Vasa Vasorum (VV), microvessles that feed the vessel wall, can indirectly image plaque inflammation and thereby significantly increase the diagnostic power of IVUS. Several studies have shown that the density of VV in the atherosclerotic plaques is strongly correlated with the intensity of plaque inflammation and related processes which lead to plaque destabilization and rupture (the Vulnerable Plaque). Therefore the detection and measurement of VV in plaque, and leakage of blood from VV into plaques using CE-IVUS, can enable the development of an index for plaque vulnerability. In this paper, we present a review of our original work on coronary VV imaging, discuss subsequent reports by others, and also present the latest on the detection of VV based on CE-IVUS.     

Effect of calcitonin in early and late stages of experimentally induced osteoarthritis. A histomorphometric study

OBJECTIVE: To investigate both prophylactic and therapeutic roles of salmon calcitonin on the articular cartilage of rabbit's knees. METHODS: Right knee instability was produced in 30 New Zealand white rabbits by sectioning the cranial cruciate ligament (CCL). Animals were separated into four groups: placebo prophylactic-stage group (n=6), killed 8 weeks post surgery, calcitonin prophylactic-stage group (n=6), treated immediately after surgery with salmon calcitonin and killed at 8 weeks, placebo therapeutic-stage group (n=9) killed at 16 weeks post surgery and calcitonin therapeutic-stage group (n=9), treated with salmon calcitonin from 8th to 16th week and killed at 16 weeks post surgery. A histomorphometric study was based on the morphological changes of the articular cartilage and subchondral bone (degeneration indexes), as well as the articular cartilage thickness, chondrocytes' arrangement and their metabolic activity (regeneration indexes). RESULTS: Calcitonin groups showed smoother articular surface, no or minimal signs of ulceration, smaller osteophytes, and less subchondral cystic formation than placebo groups. Normal distribution of chondrocytes or hypercellularity was noticed in areas of mild osteoarthritic (OA) changes in the calcitonin groups indicating regeneration activity. Periodic Acid Schiff's and Alcian blue staining were negative in the placebo groups while increased absorption in the calcitonin groups revealed high anabolic activity. CONCLUSIONS: In prophylactic stages salmon calcitonin seemed to inhibit the progression of osteoarthritis by increasing the layers of hyaline cartilage, restoring the cellular metabolism, and decreasing the volume of osteophytes. In therapeutic stages, the hormone had a healing effect by decreasing the subchondral cysts, regenerating the hyaline cartilage and restoring cellular metabolism. Both macroscopic and histological findings of this study supported the biochemical results of previous studies showing the therapeutic effect of calcitonin on osteoarthritis.     

A hypothesis for the pathogenesis and natural history of proximal tubal blockage

This paper reviews the literature on the proximal Fallopian tube and attempts to synthesize the available information into an hypothesis to elucidate the pathogenesis and natural history of proximal tubal blockage (PTB). There is evidence that the unique anatomy and physiology of the proximal Fallopian tube may predispose this tubal segment to a 'physiological' blockage, by tubal secretions and/or material back flowing from the uterine cavity, during the estrogen-dominant phase of the menstrual cycle. This would normally be reversed during the subsequent progesterone-dominant phase. However, if this reversal process is defective, organization of this material can occur, which can lead to initially incomplete and then complete tubal obstruction. Tubal wall damage does not normally exist in these cases. This sequence of events is supported by our experience in transcervical tubal cannulation. Flushing and/or guide-wiring the tubes can re-establish tubal patency and fertility. The tubal perfusion pressure, assessed during transcervical tubal cannulation procedures, can serve as a marker of the severity of PTB and the success of recanalization.     

Ultrasound-guided hydrosalpinx aspiration during oocyte collection improves pregnancy outcome in IVF: a randomized controlled trial

BACKGROUND: Hydrosalpinges have adverse effects on IVF outcomes. Salpingectomy is effective in improving outcomes, but it is not always practical or safe. Ultrasound-guided aspiration of hydrosalpinges at oocyte collection is an option for those who develop hydrosalpinges during controlled ovarian stimulation; however, there is no randomized evidence to show whether this practice is effective. METHODS: Between October 1999 and June 2003, consenting women of age 相似文献   

Effects of neonatal handling on basal and stress-induced monoamine levels in the male and female rat brain

During periods of high-frequency stimulation the maintenance of synaptic transmission depends on a continued supply of synaptic vesicles. Local recycling in the terminals ensures synaptic vesicle replenishment, but the intermediate steps are still a matter of debate. We analyzed changes in synaptic vesicle pools and endosome-like organelles near the active zone in central nerve terminals during depolarization at the ultrastructural level by electron microscopy. A short, 100 ms, depolarization-induced recruitment of synaptic vesicles was observed from a reserve pool to a recruited pool, within 150 nm of the active zone, and the docked pool at the active zone was increased as well. Prolonged, 15 s or 3 min, depolarization decreased the total amount of synaptic vesicles, which was accompanied by a parallel increase in size and amount of endosome-like organelles. After a period of rest, the number of endosome-like organelles decreased and the amount of synaptic vesicles was restored to control level.The endocytotic nature of part of the endosome-like organelles after 15 s and 3 min depolarization was indicated by their labeling with extracellularly added horseradish peroxidase (HRP). In addition, a small number of synaptic vesicles entrapped HRP under these conditions. After repolarization, the number of HRP-loaded endosome-like structures decreased. Simultaneously, a strong increase in amount of HRP-loaded small vesicles did occur.These results indicate that during sub-second depolarization, synaptic vesicles were rapidly recruited from the reserve pool to replenish the releasable pool, whereas prolonged depolarization (s-min) induced local endocytosis in at least two ways, i.e. either directly as vesicles or via endosome-like organelles from which synaptic vesicles were reformed.     

Arterial compliance is a main variable determining the effectiveness of intra-aortic balloon counterpulsation: quantitative data from an in vitro study

Quantitative data concerning the effect of arterial compliance (AC) on the effectiveness of intra-aortic balloon counterpulsation (IABC) are lacking. The main objective of this study was to investigate the relationship between AC and IABC performance. For this purpose we constructed a Windkessel, lumped-element, hydraulic model of the systemic circulation. The model consisted of a left ventricular assist device (LVAD), a compliance chamber, a peripheral resistor and two open reservoirs. Two Datascope Driving systems were used to operate the LVAD and intra-aortic balloon. We studied the effect of arterial compliance on the effectiveness of IABC at different levels of mean pressure (55, 75 and 95 mmHg) and heart rates (80, 100, 120 bpm). Three indices were used to evaluate IABC performance: the reduction of systolic and end-diastolic "arterial" pressure and the augmentation of diastolic pressure, induced by the IABC. A 22% decrease in AC (1.8-1.4 ml/mmHg) lead to a 30-40% increase in the indices of IABC performance, independently from pressure. In conclusion, arterial compliance significantly affects IABC efficacy and it could be considered as a further clinical criterion to decide IABC application.     

On the Estimation of Total Arterial Compliance from Aortic Pulse Wave Velocity

Total arterial compliance (C _T) is a main determinant of cardiac afterload, left ventricular function and arterio-ventricular coupling. C _T is physiologically more relevant than regional aortic stiffness. However, direct, in vivo, non-invasive, measurement of C _T is not feasible. Several methods for indirect C _T estimation require simultaneous recording of aortic flow and pressure waves, limiting C _T assessment in clinical practice. In contrast, aortic pulse wave velocity (aPWV) measurement, which is considered as the ??gold standard?? method to assess arterial stiffness, is noninvasive and relatively easy. Our aim was to establish the relation between aPWV and C _T. In total, 1000 different hemodynamic cases were simulated, by altering heart rate, compliance, resistance and geometry using an accurate, distributed, nonlinear, one-dimensional model of the arterial tree. Based on Bramwell?CHill theory, the formula $ C_{\text{T}} = k \cdot {\text{aPWV}}^{ - 2} $ was found to accurately estimate C _T from aPWV. Coefficient k was determined both analytically and by fitting C _T vs. aPWV data. C _T estimation may provide an additional tool for cardiovascular risk (CV) assessment and better management of CV diseases. C _T could have greater impact in assessing elderly population or subjects with elevated arterial stiffness, where aPWV seem to have limited prognostic value. Further clinical studies should be performed to validate the formula in vivo.