Elastic Properties of Aging Human Hematoma Model In Vitro and Its Susceptibility to Histotripsy Liquefaction

OBJECTIVE

Tissue susceptibility to histotripsy disintegration has been reported to depend on its elastic properties. This work was aimed at investigation of histotripsy efficiency for liquefaction of human hematomas, depending on their stiffness and degree of retraction over time (0-10 d).

METHODS

As an in vitro hematoma model, anticoagulated human blood samples (200 mL) were recalcified at different temperatures. In one set of samples, the shear modulus was measured by shear wave elastography during blood clotting at 10℃, 22℃ and 37℃, and then daily during further aging. The ultrastructure of the samples was analyzed daily with scanning electron microscopy (SEM). Another set of blood samples (50-200 mL) were recalcified at 37℃ for density and retraction measurements over aging and exposed to histotripsy at varying time points. Boiling histotripsy (2.5 ms pulses) and hybrid histotripsy (0.2 ms pulses) exposures (2 MHz, 1% dc, P+/P-/As = 182/-27/207 MPa in situ) were used to produce either individual cigar-shaped or volumetric (0.8-3 mL) lesions in samples incubated for 3 h, 5 d and 10 d. The obtained lesions were sized, then the lysate aspirated under B-mode guidance was analyzed ultrastructurally and diluted in distilled water for sizing of residual fragments.

RESULTS

It was found that clotting time decreased from 113 to 25 min with the increase in blood temperature from 10℃ to 37℃. The shear modulus increased to 0.53 ± 0.17 kPa during clotting and remained constant within 8 d of incubation at 2℃. Sample volumes decreased by 57% because of retraction within 10 d. SEM revealed significant echinocytosis but unchanged ultrastructure of the fibrin meshwork. Liquefaction rate and lesion dimensions produced with the same histotripsy protocols correlated with the increase in the degree of retraction and were lower in retracted samples versus freshly clotted samples. More than 80% of residual fibrin fragments after histotripsy treatment were shorter than 150 µm; the maximum length was 208 µm, allowing for unobstructed aspiration of the lysate with most clinically used needles.

CONCLUSION

The results indicate that hematoma susceptibility to histotripsy liquefaction is not entirely determined by its stiffness, and correlates with the retraction degree.

Influence of shock waves on bifunctional nickel particles: Enhancing magnetic properties and supercapacitor applications

In the present study, shock-wave impact experiments were conducted to investigate the structural properties of nickel metal powder when exposed to shock waves. Both X-ray diffractometry and scanning electron microscopy were used to evaluate the structural and surface morphological changes in the shock-loaded samples. Notably, the experimental results revealed variations in lattice parameters and cell structures as a function of the number of shock pulses and the increasing volume. The transition occurred from P2 (100 shocks) to P3 (200 shocks). Remarkably, P5 (400 shocks) exhibited attempts to return to its initial state, and intriguingly, P4 displayed characteristics reminiscent of the pre-shock condition. Additionally, significant morphological changes were observed with an increase in shock pulses. Magnetic measurements revealed an increase in magnetic moment for P2, P3, and P4, but a return to the original state was observed for P5. Moreover, the capacitance exhibited an upward trend with increasing shock pulses, except for P5, where it experienced a decline. These findings underscore the significant impact of even mild shock waves on the physical and chemical characteristics of bifunctional nickel particles. This research sheds light on the potential applications of shock wave-induced structural changes in enhancing the magnetic properties and supercapacitor performance of nickel particles.

Effect of superficial adipose tissue mitochondrial and cellular functionality induced by extracorporeal shock wave therapy (ESWT)

Due to its regenerative action, extracorporeal shock wave therapy (ESWT) is applied in treating integumentary and musculoskeletal diseases. However, other potential therapeutic interventions are being investigated. It is essential to fully understand its mitochondrial signaling pathway to achieve this, which plays a fundamental role in elucidating the mechanism of action and possible therapeutic interventions. Thus, this study aimed to analyze the effect of ESWT on mitochondrial pathways through the relationship between lipolysis and adipocyte apoptosis, as well as cellular functionality. This is a non-randomized case-control clinical trial where obese women received ESWT sessions in the abdominal region, after which tissue samples were collected for histological and immunohistochemical analyses of adipose tissue. The data demonstrated positivity in the expression of mitochondrial markers related to cell apoptosis, such as FIS1 (p < 0.0203) and OPA1 (p < 0.0283), in addition to the positivity of anti-MFN1, responsible for regulating mitochondrial cell proliferation (p < 0.0003). In summary, this study demonstrates that ESWT was able to activate specific mitochondrial signaling pathways, which may be associated with its ability to stimulate lipolysis and apoptosis in superficial adipose tissue. However, no significant improvements in cellular functionality were observed.

[Neurobehavioral effects of explosion exposure on acute and chronic traumatic brain injury in rats]

Objective: To explore the effect of nerve injury in rats by neurobehavioral experiments, in order to provide a model and idea for further clarification of the traumatic brain injury mechanism under explosion exposure. Methods: From May 2021 to August 2022, 160 SPF male rats were randomly divided into four groups, including control group, 60 kPa group (low intensity group), 90 kPa group (medium intensity group) and 120 kPa group (high intensity group). The blast induced traumatic brain injury (bTBI) model of rats was established by using the shock tube platform to simulate the shock wave parameters of the explosion overpressure of 60 kPa, 90 kPa and 120 kPa. Acute observation was carried out after 24 h and 7 d of explosive exposure, and chronic recovery observation was carried out after 28 d and 90 d. The time effect of shock wave brain injury in different situations was discussed by open field, light dark test, active avoidance test. Finally, the results of brain injury in rats were detected by pathological tissue staining. Results: After 24 h explosion exposure, compared with the control group, the rest time of rats in low and high intensity groups increased, the total movement distance decreased, and the number of visits to the camera obscura decreased, with statistical significance (P<0.05). After 7 days of exposure, compared with the control group, the rest time of rats in high intensity group increased, and the number of visits to the obscura decreased, with statistical significance (P<0.05). After 28 and 90 days of exposure, compared with the control group, there were no significant differences in rest time, total exercise distance and times of visiting the camera obscura in all intensity groups (P>0.05). After 24 h of explosive exposure, compared with the control group, the cell morphology of rats in each intensity group was normal, and no inflammatory cell infiltration was observed. Conclusion: In the acute phase (24 h) of blast exposure, rats have no desire to explore the outside world, and shock wave exposure may damage the neurological function of rats.

Numerical and experimental investigations on the jet and shock wave dynamics during the cavitation bubble collapsing near spherical particles based on OpenFOAM

The interaction between cavitation bubbles and particles is essential for the operational performance many kinds of fluid machineries. In the present paper, jet dynamics and shock waves induced by the cavitation bubble collapsing near two spherical particles are numerically investigated based on OpenFOAM. The numerical scheme is validated by the experimental data obtained based on our high-speed camera cavitation system. Our results reveal that bubble split induced by annular jet is the primary feature during bubble collapsing with four typical cases defined. For the jet formation, the localized high pressure produced at the bubble split point is the main reason and the split point also serves as the source of the shock waves shown by the numerical schlieren. Furthermore, the nondimensional bubble-particle distance is the most paramount parameter influencing the jet phenomenon (e.g. jet velocity).

Evidence of laser-induced nanobubble formation mechanism in water

Principles of laser-induced nanobubble formation in water are studied and presented. Nanobubbles were generated by laser light at intensities below threshold for laser-induced breakdown and subsequently expanded by a rarefaction wave to facilitate their observation and analysis. Different methods were used to study nanobubble formation and characteristics. Firstly, probability of nanobubble formation as a function of water sample purity was examined. Secondly, relation between laser fluence at different wavelengths and the number of generated nanobubbles was investigated. Thirdly, measurements of nanobubble lifetime were conducted indicating a contradiction to the Epstein-Plesset equation-based prediction of free bubble dissociation. Accumulated evidence suggests that the presence of physical impurities is a prerequisite for nanobubble formation. Consequently, a lack of impurities results in the absence of nanobubbles in contrast to assumptions by existing studies. The findings presented in this paper provide new insights into the fundamental properties of laser-induced nanobubbles in water.

Temperature as a key parameter for graphene sono-exfoliation in water

Graphene dispersions in water are highly desirable for a range of applications such as biomedicines, separation membranes, coatings, inkjet printing and more. Recent novel research has been focussed on developing a green approach for scalable production of graphene. However, one important parameter, which is often neglected is the bulk temperature of the processing liquid. This paper follows our earlier work where optimal sono-exfoliation parameters of graphite in aqueous solutions were determined based on the measured acoustic pressure fields at various temperatures and input powers. Here, we take the next step forward and demonstrate using systematic characterisation techniques and acoustic pressure measurements that sonication-assisted liquid phase exfoliation (LPE) of graphite powder can indeed produce high quality few layer graphene flakes in pure water at a specific temperature, i.e. 40 °C, and at an optimised input generator power of 50%, within 2-h of processing. UV-vis analysis also revealed that the exfoliation, stability and uniformity of dispersions were improved with increasing temperature. We further confirmed the successful exfoliation of graphene sheets with minimal level of defects in the optimized sample with the help of Raman microscopy and transmission electron microscopy. This study demonstrated that understanding and controlling processing temperature is one of the key parameters for graphene exfoliation in water which offers a potential pathway for its large-scale production.

Cavitation erosion by shockwave self-focusing of a single bubble

The ability of cavitation bubbles to effectively focus energy is made responsible for cavitation erosion, traumatic brain injury, and even for catalyse chemical reactions. Yet, the mechanism through which material is eroded remains vague, and the extremely fast and localized dynamics that lead to material damage has not been resolved. Here, we reveal the decisive mechanism that leads to energy focusing during the non-spherical collapse of cavitation bubbles and eventually results to the erosion of hardened metals. We show that a single cavitation bubble at ambient pressure close to a metal surface causes erosion only if a non-axisymmetric energy self-focusing is at play. The bubble during its collapse emits shockwaves that under certain conditions converge to a single point where the remaining gas phase is driven to a shockwave-intensified collapse. We resolve the conditions under which this self-focusing enhances the collapse and damages the solid. High-speed imaging of bubble and shock wave dynamics at sub-picosecond exposure times is correlated to the shockwaves recorded with large bandwidth hydrophones. The material damage from several metallic materials is detected in situ and quantified ex-situ via scanning electron microscopy and confocal profilometry. With this knowledge, approaches to mitigate cavitation erosion or to even enhance the energy focusing are within reach.

The effect of Extracorporeal Shock Wave Therapy in the treatment of burn scars: A prospective, randomized, controlled trial

BACKGROUND

Current scientific evidence on the effect of Extracorporeal Shock Wave Therapy (ESWT) as adjunctive treatment for burn scars is scarce. However preliminary evidence, indicates it might prove a useful tool.

MATERIALS AND METHODS

A prospective, randomized, controlled study was conducted from February 2017 to February 2019. Patients with burn scars were divided into two groups with twenty patients per group. The control group received the standard treatment for burn scars. The ESWT group received the standard treatment and treatment of burn scars with ESWT 512 impulses of 0.15mJ/mm² in each session, twice per week for 4 weeks. We assessed the appearance of scar with the Vancouver Scar Scale (VSS), pruritus and pain with Visual Analog Scale (VAS) before the start of the treatment and at 2 weeks and 5 months after the treatment.

RESULTS

Both groups showed improvements in all variables through the study. However, these improvements were only statistically significant for the VSS at the 6th month for the control group and VSS and VAS pain and pruritus for the ESWT group. Nonetheless the results failed to show statistically significant differences between the ESWT and the control group neither at two weeks after treatment nor at 5 months after treatment.

CONCLUSION

Our study questions the relevance of ESWT as adjunctive treatment for burn scars as far as outward appearance, pain and pruritus as end-results are concern. Nonetheless, further studies are required to accurately assess the potential benefits of ESWT as an adjunctive treatment for burn scars.

Shocks in the Very Local Interstellar Medium

Large-scale disturbances generated by the Sun's dynamics first propagate through the heliosphere, influence the heliosphere's outer boundaries, and then traverse and modify the very local interstellar medium (VLISM). The existence of shocks in the VLISM was initially suggested by Voyager observations of the 2-3 kHz radio emissions in the heliosphere. A couple of decades later, both Voyagers crossed the definitive edge of our heliosphere and became the first ever spacecraft to sample interstellar space. Since Voyager 1's entrance into the VLISM, it sampled electron plasma oscillation events that indirectly measure the medium's density, increasing as it moves further away from the heliopause. Some of the observed electron oscillation events in the VLISM were associated with the local heliospheric shock waves. The observed VLISM shocks were very different than heliospheric shocks. They were very weak and broad, and the usual dissipation via wave-particle interactions could not explain their structure. Estimates of the dissipation associated with the collisionality show that collisions can determine the VLISM shock structure. According to theory and models, the existence of a bow shock or wave in front of our heliosphere is still an open question as there are no direct observations yet. This paper reviews the outstanding observations recently made by the Voyager 1 and 2 spacecraft, and our current understanding of the properties of shocks/waves in the VLISM. We present some of the most exciting open questions related to the VLISM and shock waves that should be addressed in the future.

A scanning electron microscopy study of projectile entry fractures in cortical bone; genesis and microarchitectural features

The present paper presents a scanning electron microscope (SEM) analysis of the genesis and microarchitecture of experimentally induced cortical entry fractures in porcine scapulae impacted at velocities ranging from 54 to 897 m/s. SEM observation was conducted on polyurethane replicas cast from negative silicone moulds. Analysis of the sequence of fracture processes operative during projectile impact revealed the presence of ring cracks at the site of impact, confirming that penetration in sandwich bones is achieved by cone crack propagation. Despite impulsive loading, two forms of plastic deformation were identified in the cortical bone surrounding the entry fracture up to a maximum velocity of 871 m/s. Microscopic radial and concentric cracks were associated with projectile impact, and the role of pores and pits as stress concentrators was captured. Possible underlying mechanisms for the observed plastic deformation are described, and the diagnostic utility of SEM analysis is presented.

Ultrastructural Analysis of Volumetric Histotripsy Bio-effects in Large Human Hematomas

Large-volume soft tissue hematomas are a serious clinical problem, which, if untreated, can have severe consequences. Current treatments are associated with significant pain and discomfort. It has been reported that in an in vitro bovine hematoma model, pulsed high-intensity focused ultrasound (HIFU) ablation, termed histotripsy, can be used to rapidly and non-invasively liquefy the hematoma through localized bubble activity, enabling fine-needle aspiration. The goals of this study were to evaluate the efficiency and speed of volumetric histotripsy liquefaction using a large in vitro human hematoma model. Large human hematoma phantoms (85 cc) were formed by recalcifying blood anticoagulated with citrate phosphate dextrose/saline-adenine-glucose-mannitol solution. Typical boiling histotripsy pulses (10 or 2 ms) or hybrid histotripsy pulses using higher-amplitude and shorter pulses (0.4 ms) were delivered at 1% duty cycle while continuously translating the HIFU focus location. Histotripsy exposures were performed under ultrasound guidance with a 1.5-MHz transducer (8-cm aperture, F# = 0.75). The volume of liquefied lesions was determined by ultrasound imaging and gross inspection. Untreated hematoma samples and samples of the liquefied lesions aspirated using a fine needle were analyzed cytologically and ultrastructurally with scanning electron microscopy. All exposures resulted in uniform liquid-filled voids with sharp edges; liquefaction speed was higher for exposures with shorter pulses and higher shock amplitudes at the focus (up to 0.32, 0.68 and 2.62 mL/min for 10-, 2- and 0.4-ms pulses, respectively). Cytological and ultrastructural observations revealed completely homogenized blood cells and fibrin fragments in the lysate. Most of the fibrin fragments were less than 20 μm in length, but a number of fragments were up to 150 μm. The lysate with residual debris of that size would potentially be amenable to fine-needle aspiration without risk for needle clogging in clinical implementation.

Effect of extracorporeal shock waves on inflammation and angiogenesis of integumentary tissue in obese individuals: stimulating repair and regeneration

The technology of extracorporeal shock wave therapy (ESWT) has been studied around the world for its possible benefits in the treatment and rehabilitation of aesthetic disorders. To better elucidate its real physiological effect on the integumentary tissue, this study was proposed aimed at evaluating whether ESWT can act to stimulate the inflammatory process and angiogenesis in the dermis and epidermis of obese individuals. This is an immunohistological study that evaluated a set of samples of the integumentary tissue of women with grade II obesity with weight loss of 10% of the initial weight undergoing ESWT treatment; the collection of biological material was performed at the time of surgery of bariatric surgery. For immunohistochemical evaluation, the markers to assess the presence and distribution of inflammatory cells, anti-COX-2, CD3, CD20, CD163, and NK were used. For physiological stimulus pathways for blood vessel angiogenesis, markers CD 34, CD 105 and VEGF were used. Fourteen obese women were included in the study. Positivity was evidenced in the epidermal expression of markers of the inflammatory process COX-2, CD3, CD20, NK cells, CD68, and CD163 (p < 0.0001) in the intervention sample when compared to controls. There was a positive expression for the angiogenesis markers CD105 and VEGF (p < 0.0001) when comparing the intervention group with the control group. It was concluded that ESWT can stimulate a local inflammatory process, mediating and modulating important growth factors to act in the repair process and skin tissue regeneration, being considered a promising treatment for skin diseases related to weight gain or loss.

Therapeutic modality of induced uterine leiomyoma with shock waves in rats: The uterine blood flow, circulating ovarian hormones and histopathological findings

Uterine leiomyoma is the most common benign pelvic tumor and the primary indication for hysterectomy. We hypothesized tumor softening and shrinking through shock waves mechanobiological influence on fibroblasts of the induced leiomyoma in rats. Three rats served as control from thirty-three female Wistar rats subjected to leiomyoma induction using mono-sodium glutamate and estradiol benzoate. After assessing uterine leiomyoma development with Doppler ultrasonography, blood and tissue samples were collected for hormonal and histopathological analysis. Of the fifteen rats treated with shock waves, five rats were sacrificed after receiving two sessions (2S), another five rats were sacrificed after receiving four sessions (4S), and the last five rats were sacrificed after two weeks recovery period (recovered 4S). From the fifteen non-treated leiomyoma group, five rats were sacrificed after Doppler ultrasound assessment (Leiomyoma), another five rats were sacrificed with the 4S group (Leiomyoma 1Wk recovery), and the last five rats were sacrificed with the recovered 4S group (Recovered leiomyoma). The collected blood samples, estradiol (E2), Estrogen receptor, progesterone (P4), and progesterone receptor (PGR), were assayed. Total cholesterol, protein, albumin, and globulin were measured. Uterine arteries' blood flow velocities, indices, and volume were obtained. Tissue samples were stained with smooth muscle actin (SMA), trichrome-three, and (hematoxylin and eosin). Rats developed leiomyoma had the highest (P = 0.0001) gross and sonographic uterine horns diameters, uterine weight, uterine coefficient, E2, and ER. Both trichrome-three and SMA staining confirmed the leiomyoma development and the response to shock waves treatment. In conclusion, low-intensity shock waves proved curative to the induced leiomyoma.

On the governing fragmentation mechanism of primary intermetallics by induced cavitation

One of the main applications of ultrasonic melt treatment is the grain refinement of aluminium alloys. Among several suggested mechanisms, the fragmentation of primary intermetallics by acoustic cavitation is regarded as very efficient. However, the physical process causing this fragmentation has received little attention and is not yet well understood. In this study, we evaluate the mechanical properties of primary Al3Zr intermetallics by nano-indentation experiments and correlate those with in-situ high-speed imaging (of up to 1 Mfps) of their fragmentation process by laser-induced cavitation (single bubble) and by acoustic cavitation (cloud of bubbles) in water. Intermetallic crystals were chemically extracted from an Al-3 wt% Zr alloy matrix. Mechanical properties such as hardness, elastic modulus and fracture toughness of the extracted intermetallics were determined using a geometrically fixed Berkovich nano-diamond and cube corner indenter, under ambient temperature conditions. The studied crystals were then exposed to the two cavitation conditions mentioned. Results demonstrated for the first time that the governing fragmentation mechanism of the studied intermetallics was due to the emitted shock waves from the collapsing bubbles. The fragmentation caused by a single bubble collapse was found to be almost instantaneous. On the other hand, sono-fragmentation studies revealed that the intermetallic crystal initially underwent low cycle fatigue loading, followed by catastrophic brittle failure due to propagating shock waves. The observed fragmentation mechanism was supported by fracture mechanics and pressure measurements using a calibrated fibre optic hydrophone. Results showed that the acoustic pressures produced from shock wave emissions in the case of a single bubble collapse, and responsible for instantaneous fragmentation of the intermetallics, were in the range of 20-40 MPa. Whereas, the shock pressure generated from the acoustic cavitation cloud collapses surged up to 1.6 MPa inducing fatigue stresses within the crystal leading to eventual fragmentation.

Spectroscopic assessment on the stability of benzophenone crystals at shock waves loaded condition

In recent years, there have been few thousands of non-linear optical (NLO) materials proposed for a wide array of technological applications. But unfortunately, most of the materials do not fit into the actual standard required for the specific purposes in terms of their efficiency, environmental resistance, cost effectiveness, availability, stability and durability. Hence, searching for the most suitable material for every specific technological application has become the necessity of being a continuous process until it is found. For the present experiment, we have chosen benzophenone crystal for the shock wave recovery experiment. Raman and powder X-ray diffraction (XRD) techniques have been utilized to evaluate the molecular and structural performances of the title material against the impact of shock waves and the obtained crystallographic structural properties are compared with potassium dihydrogen phosphate (KPD) crystal. The obtained Raman and XRD results demonstrate that the title material has high shock resistant property even though it is a mechanically soft material as well as it has very low melting point (48 °C).

Does radial shock wave therapy works in pseudarthrosis? Prospective analysis of forty four patients

INTRODUCTION

In this study, we analyze a new treatment option for pseudarthrosis using radial shock waves. The traditional treatment to pseudarthrosis is surgical. As an option to specific cases, focal shock waves seem to present good results with bone union without a subsequent surgical procedure. As radial shock waves reach less energy and less depth penetration than focal shock waves, they usually are not indicated for the treatment of pseudarthrosis of any bone segment. There are publications that show evidences of the action of radial shock waves stimulating bone consolidation in vitro, in animals and in humans. We will present a new option for failure of consolidation in superficial bones submitted to radial shock wave therapy.

OBJECTIVE

To analyze the effectiveness of radial shock waves in the treatment of superficial bone pseudarthrosis.

PATIENTS AND METHODS

Between 2016 and 2019, we conducted a prospective study with 44 consecutive patients with pseudarthrosis. All patients had prior indication for treatment with surgery and were treated with radial shock waves as a nonsurgical treatment option. Patients were evaluated clinically and radiographically pre-treatment and 6 months after. Clinically, patients complained of pain and dysfunction, according to the segment affected, and radiographically, evidences of pseudarthrosis in at least two X-ray views. As the outcomes: satisfactory when there was bone union, no pain, and return function; unsatisfactory when there was no bone union and maintain pain and dysfunction. All patients were treated with the same equipment and by the same physician. The treatment consisted in 3 sessions with weekly interval; in each session, 3000 radial shock waves were applied with 4 bar of energy.

RESULTS

After 6 months, clinical analysis and X-ray evidence on 77.2% of the patients presented bone union and clinical improvement classified as satisfactory result. There were no complications.

CONCLUSION

Treatment of pseudarthrosis in superficial bones with radial shock waves is effective and safe.

An in vitro model of temporal enhancement of epithelium barrier permeability by low-energy shock waves without contrast agents

One of the commonly used techniques for drug delivery is to temporarily increase the permeability of tissue barriers. Acoustic energies such as ultrasound and shock waves are known to modulate tissue permeability. Recently, it was found that shock waves modulate the blood-brain barrier in the rat brain without injection of contrast agents such as microbubbles. This finding implies that modulation of other tissue barriers by shock wave exposure without contrast agents may be possible. To examine whether the modulation is also possible with other tissue barriers, we here investigated whether shock waves would modulate an in vitro tissue barrier model consisting of epithelial cells cultured on culture inserts. The permeability of the epithelium sheets evaluated by trans-epithelial electrical resistance (TEER) was increased following shock waves at a peak pressure of 11 MPa. The increased permeability recovered within 2 h. This enhancement was realized with one-shot low-energy shock waves having an acoustic energy of 0.013 mJ/mm². Monitoring the peak pressures in every exposure revealed that the minimum peak pressure required for the enhancement is 2.9 MPa. These results indicate that shock wave exposure has the potential to temporarily increase the permeability of epithelium barriers to enhance drug delivery without contrast agents. Graphical abstract Enhancements of epithelial barrier permeability were evaluated by trans-epithelial electrical resistance (TEER) before and after shock wave exposures.

A novel mouse model of mild traumatic brain injury using laser-induced shock waves

Blast-induced mild traumatic brain injury (mild bTBI) has been a frequent battlefield injury in soldiers during the conflicts in Iraq and Afghanistan. Understanding the pathophysiology and determining effective treatments for mild bTBI has become an international problem in the field of neurotrauma research. Contributing to this problem is a lack of an experimental model that accurately mimics the characteristics of mild bTBI. To date, the "mild'' versions of common experimental models of TBI have simply been less severe degrees of traumatic injury; these animals do not necessarily exhibit the clinical characteristics of mild bTBI seen in humans. Therefore, our first objective was to develop a highly controlled mouse model of bTBI using laser-induced shockwaves (LISWs). We established the parameters necessary to cause a reproducible injury of very mild severity, the most important feature seen in clinical practice. We defined very mild bTBI as having no traumatic change on the head visible to the naked eye after the insult was applied using very mild shockwaves to the heads of mice. Our very mild bTBI mouse model exhibited neurobehavioral changes in the chronic phase, such as cognitive impairment and depression-like behavior. We also observed an increase in 5-bromo-2'-deoxyuridine-positive, proliferating cells in the dentate gyrus during the acute phase and a subsequent decrease during the chronic phase. This model appears to be an accurate representation of the damage occurring in actual mild bTBI patients. We also found that an increase in cell proliferation in the dentate gyrus during the acute phase is the most prominent feature after a TBI.

A randomized controlled trial: comparing extracorporeal shock wave therapy versus local corticosteroid injection for the treatment of carpal tunnel syndrome

PURPOSE

Extracorporeal shock wave therapy (ESWT) has been reported as a new therapy for carpal tunnel syndrome (CTS). However, few studies have compared ESWT with the local corticosteroid injection (LCI).

METHODS

In this study, a randomized controlled trial comparing 30 patients with ESWT and 25 patients treated with LCI was conducted. The clinical outcomes were obtained with tests including the visual analog scale (VAS) for pain and paresthesia, the Boston Carpal Tunnel Questionnaire (BQ), and a nerve conduction study, before the study started and at three, nine, and 12 weeks after the start of the treatment.

RESULTS

Significantly greater improvement in the VAS and BQ scores was noted for the ESWT group than for the LCI group (P < 0.05). For the nerve conduction study, there was a significant improvement in the median nerve sensory nerve action potential distal latency at the nine and 12-week follow-ups for the ESWT group.

CONCLUSIONS

ESWT is a useful noninvasive short-term treatment for mild to moderate carpal tunnel syndrome and elicits a better recovery than LCI does, but more research is needed to test the clinical outcomes of ESWT.

Extracorporeal shock wave therapy role in the treatment of burn patients. A systematic literature review

INTRODUCTION

Extracorporeal shock wave therapy (ESWT), first described in the eighties for the treatment of urolithiasis, has also been applied in other fields such as orthopaedics and chronic wound care. Recently it has also been used in the treatment of burns and its sequelae since several studies suggest it could be an important tool in the conservative management of these conditions. The aim of this article is to review the literature for published evidence on the use of ESWT for the treatment of acute burn patients and its sequelae and to elaborate a brief report on the current state of the matter.

MATERIAL AND METHODS

We carried on a search on PUBMED database and Cochrane database with the following terms: ('burns' [title/abstract] OR 'burn' [title/abstract]) AND "shock wave" ([title/abstract]). For an optimal reporting of the studies found we followed the PRISMA statement.

RESULTS

This search found 34 articles from which only 15 were actually related to the use of ESWT in burn patients. From these 15 articles, 7 involved the use of ESWT in the treatment of acute burns, 6 related to its application in post-burn scars, 1 in the treatment of heterotopic ossification and 1 was about the use of ESWT in skin-graft donor site. Except for the latter, all of them were carefully reviewed.

CONCLUSION

Scientific evidence on the use of ESWT for the treatment of burn patients is weak due to the paucity of studies and their low quality. However, ESWT seems to be a promising tool in this field and therefore more high-quality trials should be conducted.

Fragmentation of brittle material by shock wave lithotripsy. Momentum transfer and inertia: a novel view on fragmentation mechanisms

Shock wave lithotripsy is the only non-invasive stone therapy and in clinical use since 1980. In spite of decades with millions of patients treated, the mechanism of fragmentation is still under debate. Detailed knowledge of the fragmentation process is required for improvements regarding safety and efficiency. The purpose of this paper is to gain a deeper insight into the mechanism of fragmentation by drawing attention to basic physical laws of inertia and momentum transfer. Many fragmentation experiments are based on the overall efficiency of multiple shock waves in crushing kidney stones or artificial model stones utilizing small baskets or latex pouches. Due to the high dynamic nature of the fragmentation process, in vitro and in vivo, a detailed action of a single shock wave on a particular stone target is difficult to investigate. We utilized a bifilar stone suspension, which allowed us to observe horizontal movements of model stones, their return to the initial position and orientation for repeated exposure of separate identical shocks. The method does not describe the entire fragmentation process in detail but elucidates a mechanism, which may be effective throughout shock wave lithotripsy in general. Measurements on model stones in water revealed forces in the range of 370 N, acceleration values of 100,000-200,000 m/s² (≈ 10,000 g) and gained momentum of 3.7 × 10^- 4 kg m/s we consider sufficient to break most human urinary stones. Fracture patterns of repeated identical shock waves show typical features supporting spallation (Hopkinson effect) and the mechanism of momentum transfer. Schlieren and photo-elastic images provide a visual impression of spatial stress in a transparent acrylic glass cylinder, cavitation fields outside and at the surface of the cylinder, which are compatible with the inertia model. The proposed mechanism covers coarse as well as fine fragmentation. Collapsing cavitation bubbles may have an impact on the fragmentation process but although expected, a direct action of micro-jets on sample surfaces could not be detected.

Stimulation of angiogenesis using single-pulse low-pressure shock wave treatment

Endothelial cells respond to mechanical stimuli such as stretch. This property can be exploited with caution to induce angiogenesis which will have immense potential to treat pathological conditions associated with insufficient angiogenesis. The primary aim of this study is to test if low-pressure shock waves can be used to induce angiogenesis. Using a simple diaphragm-based shock tube, we demonstrate that a single pulse of low pressure (0.4 bar) shock wave is enough to induce proliferation in bovine aortic endothelial cells and human pulmonary microvascular endothelial cells. We show that this is associated with enhanced Ca⁺⁺ influx and phosphorylation of phosphatidylinositol-3-kinase (PI3K) which is normally observed when endothelial cells are exposed to stretch. We also demonstrate the pro-angiogenic effect of shock waves of single pulse (per dose) using murine back punch wound model. Shock wave treated mice showed enhanced wound-induced angiogenesis as reflected by increased vascular area and vessel length. They also showed accelerated wound closure compared to control mice. Overall, our study shows that just a single pulse/shot (per dose) of shock waves can be used to induce angiogenesis. Importantly, we demonstrate this effect using a pulse of low-pressure shock waves (0.4 bar, in vitro and 0.15 bar, in vivo). KEY MESSAGES: Low-pressure single-pulse shock waves can induce endothelial cell migration and proliferation. This effect is endothelial cell specific. These shock waves enhance wound-induced angiogenesis in vivo. These shock waves can also accelerate wound healing in vivo.

Shock wave-induced permeabilization of mammalian cells

Controlled permeabilization of mammalian cell membranes is fundamental to develop gene and cell therapies based on macromolecular cargo delivery, a process that emerged against an increasing number of health afflictions, including genetic disorders, cancer and infections. Viral vectors have been successfully used for macromolecular delivery; however, they may have unpredictable side effects and have been limited to life-threatening cases. Thus, several chemical and physical methods have been explored to introduce drugs, vaccines, and nucleic acids into cells. One of the most appealing physical methods to deliver genes into cells is shock wave-induced poration. High-speed microjets of fluid, emitted due to the collapse of microbubbles after shock wave passage, represent the most significant mechanism that contributes to cell membrane poration by this technique. Herein, progress in shock wave-induced permeabilization of mammalian cells is presented. After covering the main concepts related to molecular strategies whose applications depend on safer drug delivery methods, the physics behind shock wave phenomena is described. Insights into the use of shock waves for cell membrane permeation are discussed, along with an overview of the two major biomedical applications thereof-i.e., genetic modification and anti-cancer shock wave-assisted chemotherapy. The aim of this review is to summarize 30 years of data showing underwater shock waves as a safe, noninvasive method for macromolecular delivery into mammalian cells, encouraging the development of further research, which is still required before the introduction of this promising tool into clinical practice.

Mesenchymal stem cells as therapeutic target of biophysical stimulation for the treatment of musculoskeletal disorders

BACKGROUND

Musculoskeletal disorders are regarded as a major cause of worldwide morbidity and disability, and they result in huge costs for national health care systems. Traditional therapies frequently turned out to be poorly effective in treating bone, cartilage, and tendon disorders or joint degeneration. As a consequence, the development of novel biological therapies that can treat more effectively these conditions should be the highest priority in regenerative medicine. Mesenchymal stem cells (MSCs) represent one of the most promising tools in musculoskeletal tissue regenerative medicine, thanks to their proliferation and differentiation potential and their immunomodulatory and trophic ability. Indeed, MSC-based approaches have been proposed for the treatment of almost all orthopedic conditions, starting from different cell sources, alone or in combination with scaffolds and growth factors, and in one-step or two-step procedures. While all these approaches would require cell harvesting and transplantation, the possibility to stimulate the endogenous MSCs to enhance their tissue homeostasis activity represents a less-invasive and cost-effective therapeutic strategy. Nowadays, the role of tissue-specific resident stem cells as possible therapeutic target in degenerative pathologies is underinvestigated. Biophysical stimulations, and in particular extracorporeal shock waves treatment and pulsed electromagnetic fields, are able to induce proliferation and support differentiation of MSCs from different origins and affect their paracrine production of growth factors and cytokines.

SHORT CONCLUSIONS

The present review reports the attempts to exploit the resident stem cell potential in musculoskeletal pathologies, highlighting the role of MSCs as therapeutic target of currently applied biophysical treatments.

The Application of Clinical Lithotripter Shock Waves to RNA Nucleotide Delivery to Cells

The delivery of genes into cells through the transfer of ribonucleic acids (RNAs) has been found to cause a change in the level of target protein expression. RNA-based transfection is conceptually more efficient than commonly delivered plasmid DNA because it does not require division or damage of the nuclear envelope, thereby increasing the chances of the cell remaining viable. Shock waves (SWs) have been found to induce cellular uptake by transiently altering the permeability of the plasma membrane, thereby overcoming a critical step in gene therapy. However, accompanying SW bio-effects include dose-dependent irreversible cell injury and cytotoxicity. Here, the effect of SWs generated by a clinical lithotripter on the viability and permeabilisation of three different cell lines in vitro was investigated. Comparison of RNA stability before and after SW exposure revealed no statistically significant difference. Optimal SW exposure parameters were identified to minimise cell death and maximise permeabilisation, and applied to enhanced green fluorescent protein (eGFP) messenger RNA (mRNA) or anti-eGFP small interfering RNA delivery. As a result, eGFP mRNA expression levels increased up to 52-fold in CT26 cells, whereas a 2-fold decrease in GFP expression was achieved after anti-eGFP small interfering RNA delivery to MCF-7/GFP cells. These results indicate that SW parameters can be employed to achieve effective nucleotide delivery, laying the foundation for non-invasive and high-tolerability RNA-based gene therapy.

Effect of Frequency-Dependent Attenuation on Predicted Histotripsy Waveforms in Tissue-Mimicking Phantoms

Tissue-mimicking phantoms are employed for the assessment of shocked histotripsy pulses in vitro. These broadband shock waves are critical for tissue ablation and are influenced by the frequency-dependent attenuation of the medium. The density, sound speed and attenuation spectra (2-25 MHz) were measured for phantoms that mimic key histotripsy targets. The influence of non-linear propagation relative to the attenuation was described in terms of Gol'dberg number. An expression was derived to estimate the bandwidth of shocked histotripsy pulses for power law-dependent attenuation. The expression is independent of the fundamental frequency of the histotripsy pulse for linear frequency-dependent attenuation.

Thoracic shock wave injury causes behavioral abnormalities in mice

BACKGROUND

Mild traumatic brain injury (mTBI) is caused by complex mechanisms of systemic, local and cerebral responses to blast exposure. However, the molecular mechanisms of cognitive impairment after exposure to blast waves are not clearly known. We tested the hypothesis that thoracic injury induced functional and morphological impairment in the brain, leading to behavioral abnormalities.

METHODS

Mice were exposed to laser-induced shock waves (LISWs) impacting the thorax and assessed for behavioral outcome at 7 and 28 days post injury. Hippocampus and lung were collected for histopathological analysis and gene expression profiling after injury.

RESULTS

Thoracic injury transiently decreased the heart rate, blood pressure, peripheral oxyhemoglobin saturation and cerebral blood flow immediately after LISW exposure. Although LISWs exposure caused pulmonary contusions, hemorrhage was not apparent in the brain. At 7 and 28 days after, the injured mice exhibited impaired short-term memory and depression-like behavior compared with controls. Histological assessments showed an increase in neuronal cell death after shock wave exposure, especially in the CA3 region of the hippocampus. Moreover, shock wave exposure altered the expression of functionally relevant genes in the hippocampus at 1 h and 1 day post injury.

CONCLUSIONS

Our findings indicate that the LISW-induced thoracic injury with no direct impact on the brain affected the hippocampal gene expression and led to morphological alterations, resulting in behavioral abnormalities. Therefore, body protection may be extremely important in the effective prevention against blast-induced alterations in brain function.

Shock wave as biological therapeutic tool: From mechanical stimulation to recovery and healing, through mechanotransduction

Extracorporeal Shock Wave Therapy (ESWT) is a form of "mechanotherapy", that, from its original applications as urological lithotripsy, gained the field of musculo-skeletal diseases as Orthotripsy (mainly tendinopaties and bone regenerative disorders) and Regenerative Medicine as well. The mechanisms of action of Shock Waves (SW), when applied in non-urological indications, are not related to the direct mechanical effect, but to the different pathways of biological reactions, that derive from that acoustic stimulations, through "mechano-transduction". So, the "mechanical model" of urological lithotripsy has been substituted by a "biological model", also supported by current knowledge in "mechanobiology", the emerging multidisciplinary field of science that investigates how physical forces and changes in cell/tissue mechanics can influence the tissue development, physiology and diseases. Although some details are still under study, it is known that SW are able to relief pain, as well to positively regulate inflammation (probably as immunomodulator), to induce neoangiogenesis and stem cells activities, thus improving tissue regeneration and healing. ESWT can be nowadays considered an effective, safe, versatile, repeatable, noninvasive therapy for the treatment of many musculo-skeletal diseases, and for some pathological conditions where regenerative effects are desirable, especially when some other noninvasive/conservative therapies have failed. Moreover, based on the current knowledge in SW mechanobiology, it seems possible to foresee new interesting and promising applications in the fields of Regenerative Medicine, tissue engineering and cell therapies.

Changes in Urolithiasis Referral Patterns for Shock Wave Lithotripsy over a Decade: Was There Adherence to AUA/EAU Guidelines?

OBJECTIVE

The primary objective was to assess changes in referral patterns of urolithiasis for shock wave lithotripsy (SWL) over a decade. The secondary objective was to evaluate the effect of the number of years of practice of referring physicians on these referral patterns.

METHODS

A retrospective review of SWL database was performed for consecutive referrals for SWL at a tertiary stone center between December 1999 and December 2013. Patient demographics and stone characteristics were assessed. The stone location at the time of referral was used as the reference. Retreatments were excluded. In addition, years of practice of the referring physicians were calculated. The 2007 AUA/EAU guidelines on urolithiasis were considered as a reference.

RESULTS

A total of 8,992 SWL treatments were included. After December 2007, there was a significant increase in the percentage of renal pelvic stones referred for SWL (23.0 vs. 27.1%, p < 0.001). Conversely, proximal ureteral stones significantly decreased after 2007 (24 vs. 18.2%, p < 0.001) including stones > 10 mm (5.1 vs. 2.9%, p < 0.001). Otherwise, there were no changes in the referral patterns for SWL of other stone locations before and after December 2007 (p > 0.05). Furthermore, percentage of stones referred for SWL by urologists practicing for less than 10 years significantly decreased after December 2007 (29.5 vs. 22.8%, p < 0.001).

CONCLUSIONS

The significant reduction in the referral of proximal ureteral stones after December 2007 corresponds to the latest AUA/EAU guidelines on management of ureteral stones.

Effect of shock waves on macrophages: A possible role in tissue regeneration and remodeling

INTRODUCTION

Extracorporeal Shock Wave Therapy (ESWT) is broadly used as a non-surgical therapy in various diseases for its pro-angiogenic and anti-inflammatory effects. However, the molecular mechanisms translating tissue exposure to shock waves (SW) in a biological response with potential therapeutic activity are largely unknown. As macrophages take part in both the onset and amplification of the inflammatory response, and well in its resolution, we investigated the effect of SW on their biology.

METHODS

Human monocyte-derived macrophages were polarized to classic (M1) pro-inflammatory macrophages or alternative (M2) anti-inflammatory macrophages and exposed to SW ad different intensities. Expression levels of marker genes of macrophage activation were measured by qPCR at different time points.

RESULTS

SW did not induce activation of resting macrophages at any energy level used. Conversely, when used at low energy SW caused a significant inhibition of some M1 marker genes (CD80, COX2, CCL5) in M1 macrophages and a significant synergistic effect for some M2 marker genes (ALOX15, MRC1, CCL18) in M2 macrophages. SW also affected cytokine and chemokine production, inducing in particular a significant increase in IL-10 and reduction in IL-1β production.

CONCLUSIONS

Macrophage exposure to low energy SW dampens the induction of the pro-inflammatory profile characterizing M1 macrophages and promotes the acquisition of an anti-inflammatory profile synergizing with macrophage alternative activation.

Recombinant expression of four oxidoreductases in Phanerochaete chrysosporium improves degradation of phenolic and non-phenolic substrates

Phanerochaete chrysosporium belongs to a group of lignin-degrading fungi that secretes various oxidoreductive enzymes, including lignin peroxidase (LiP) and manganese peroxidase (MnP). Previously, we demonstrated that the heterologous expression of a versatile peroxidase (VP) in P. chrysosporium recombinant strains is possible. However, the production of laccases (Lac) in this fungus has not been completely demonstrated and remains controversial. In order to investigate if the co-expression of Lac and VP in P. chrysosporium would improve the degradation of phenolic and non-phenolic substrates, we tested the constitutive co-expression of the lacIIIb gene from Trametes versicolor and the vpl2 gene from Pleurotus eryngii, and also the endogenous genes mnp1 and lipH8 by shock wave mediated transformation. The co-overexpression of peroxidases and laccases was improved up to five-fold as compared with wild type species. Transformant strains showed a broad spectrum in phenolic/non-phenolic biotransformation and a high percentage in synthetic dye decolorization in comparison with the parental strain. Our results show that the four enzymes can be constitutively expressed in a single transformant of P. chrysosporium in minimal medium. These data offer new possibilities for an easy and efficient co-expression of laccases and peroxidases in suitable basidiomycete species.

Prognostic factors of extracorporeal shock wave therapy for tendinopathies

INTRODUCTION

Extracorporeal shock wave therapy is very widely used for the management of tendinopathies and plantar fasciitis.

AIM

The aim of the study is to determine whether there are prognostic factors that may influence the outcome of extracorporeal shock wave therapy for these diseases.

METHODS

Three hundred fifty-five patients were analyzed 2 months after shock wave treatment for rotator cuff tendinitis, epicondylitis, Achilles tendinopathy, trocanteritis, jumper's knee or plantar fasciitis. We recorded the epidemiological, clinical and treatment protocol, and these data were correlated with treatment outcome.

RESULTS

Clinical improvement was achieved in 45.9 % of these patients. We discovered that laterality different to the dominant limb (p < 0.0001) and repeated shock wave treatments (p = 0.004) are prognostic factors in an unsuccessful therapy, while being male (p = 0.015) and a high body mass index (p = 0.004) are factors for success. We found no differences in relation to age, diet, blood type, work or sport activity, presence of co-morbidities, drugs, type of tendinopathy, density of energy delivered and other physiotherapy treatment. Knowledge of these prognostic factors may lead to improved insight for physicians and physiotherapists to predict the extent of the recovery and adjust rehabilitation and patient expectations accordingly.

Effects of extracorporeal shock wave therapy on functional recovery and neurotrophin-3 expression in the spinal cord after crushed sciatic nerve injury in rats

The study described here investigated the effects of extracorporeal shock wave therapy (ESWT) on functional recovery and neurotrophin-3 expression in the spinal cord after sciatic nerve injury in rats. Forty-five 8-wk-old rats were used and randomly divided into three groups: An experimental group, a control group and a sham group. The experimental group received ESWT after the nerve-crushing damage. The sciatic functional index and Dartfish Software were used to determine the effect of sciatic nerve damage on functional changes. A 1-cm length of spinal cord encompassing the L4-6 level was removed for Western blot analysis. The sciatic functional index significantly changed in both the ESWT and control groups after impairment. In the time course evaluation of the ankle angle in the toe off, the ESWT group had statistically significant increases from day 21 onward. There was a significant difference in neurotrophin-3 expression between the groups on days 1, 7 and 14 after impairment. Early application of ESWT increased the expression of neurotrophin-3 and neurotrophin-3 mRNA, and daily therapy facilitated the activity of macrophages and Schwann cells, which affect the survival and regeneration of neurons.

In vivo effects of focused shock waves on tumor tissue visualized by fluorescence staining techniques

Shock waves can cause significant cytotoxic effects in tumor cells and tissues both in vitro and in vivo. However, understanding the mechanisms of shock wave interaction with tissues is limited. We have studied in vivo effects of focused shock waves induced in the syngeneic sarcoma tumor model using the TUNEL assay, immunohistochemical detection of caspase-3 and hematoxylin-eosin staining. Shock waves were produced by a multichannel pulsed-electrohydraulic discharge generator with a cylindrical ceramic-coated electrode. In tumors treated with shock waves, a large area of damaged tissue was detected which was clearly differentiated from intact tissue. Localization and a cone-shaped region of tissue damage visualized by TUNEL reaction apparently correlated with the conical shape and direction of shock wave propagation determined by high-speed shadowgraphy. A strong TUNEL reaction of nuclei and nucleus fragments in tissue exposed to shock waves suggested apoptosis in this destroyed tumor area. However, specificity of the TUNEL technique to apoptotic cells is ambiguous and other apoptotic markers (caspase-3) that we used in our study did not confirmed this observation. Thus, the generated fragments of nuclei gave rise to a false TUNEL reaction not associated with apoptosis. Mechanical stress from high overpressure shock wave was likely the dominant pathway of tumor damage.

Shock waves and DNA-cationic lipid assemblies: a synergistic approach to express exogenous genes in human cells

Cationic lipid/DNA complexes (lipoplexes) represent a powerful tool for cell transfection; however, their use is still limited by important concerns, including toxicity and poor internalization into deep tissues. In this work, we investigated the use of shock wave-induced acoustic cavitation in vitro for the transfection of lipoplexes in human embryo kidney 293 cells. We selected shock waves with the ability to internalize 10-kDa fluorescein isothiocyanate-dextran into cells while maintaining survival rates above 50%. Cell transfection was tested using the green fluorescent protein-encoding plasmid pCX::GFPGPI2. Confocal microscopy and fluorescence-assisted cell sorting analyses revealed successful transfection after treatments ranging from 1 to 3 min using 60 to 180 shock waves at peak amplitudes of 12.3 ± 1.5 MPa. Interestingly, the combination of shock waves and lipoplexes induced a 3.1- and 3.8-fold increase in the expression of the reporter gene compared with the use of lipoplexes or shock waves alone, respectively. These results indicate that cationic DNA assembly and shock waves act in a synergistic manner to promote transfection of human cells, revealing a potential approach for non-invasive site-specific gene therapy.

Super- and sub-critical regions in shocks driven by radio-loud and radio-quiet CMEs

White-light coronagraphic images of Coronal Mass Ejections (CMEs) observed by SOHO/LASCO C2 have been used to estimate the density jump along the whole front of two CME-driven shocks. The two events are different in that the first one was a “radio-loud” fast CME, while the second one was a “radio quiet” slow CME. From the compression ratios inferred along the shock fronts, we estimated the Alfvén Mach numbers for the general case of an oblique shock. It turns out that the “radio-loud” CME shock is initially super-critical around the shock center, while later on the whole shock becomes sub-critical. On the contrary, the shock associated with the “radio-quiet” CME is sub-critical at all times. This suggests that CME-driven shocks could be efficient particle accelerators at the shock nose only at the initiation phases of the event, if and when the shock is super-critical, while at later times they lose their energy and the capability to accelerate high energetic particles.