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1.
mBio ; : e0254723, 2023 Nov 14.
Article in English | MEDLINE | ID: mdl-37962347

ABSTRACT

IMPORTANCE: Malaria is a devastating disease that has claimed many lives, especially children <5 years of age in Sub-Saharan Africa, as documented in World Malaria Reports by WHO. Even though vector control and chemoprevention tools have helped with elimination efforts in some, if not all, endemic areas, these efforts have been hampered by serious issues (including drug and insecticide resistance and disruption to social cohesion caused by the COVID-19 pandemic). Development of an effective malaria vaccine is the alternative preventative tool in the fight against malaria. Vaccines save millions of lives each year and have helped in elimination and/or eradication of global diseases. Development of a highly efficacious malaria vaccine that will ensure long-lasting protective immunity will be a "game-changing" prevention strategy to finally eradicate the disease. Such a vaccine will need to counteract the significant obstacles that have been hampering subunit vaccine development to date, including antigenic polymorphism, sub-optimal immunogenicity, and waning vaccine efficacy.

2.
PeerJ ; 11: e16001, 2023.
Article in English | MEDLINE | ID: mdl-37701830

ABSTRACT

Following school closures and changes in contact behavior of children and adults a reduced head louse prevalence has been reported from across the globe. In parallel, sales of treatments were observed to fall, partly because of supply problems of some products following the pandemic, but this did not appear to result in more cases of infestation. Surveys of schools in and around Cambridge, UK, found that infestation rates were significantly reduced particularly in city schools compared with similar surveys conducted before the COVID-19 pandemic. Contrary to expectation the number of cases in schools has only risen slowly since schools returned to normal full time working in 2022-2023.


Subject(s)
COVID-19 , Lice Infestations , Pediculus , Adult , Child , Animals , Humans , Pandemics/prevention & control , Prevalence , COVID-19/epidemiology , Lice Infestations/epidemiology , United Kingdom/epidemiology
4.
Mol Oncol ; 17(10): 1947-1949, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37766480

ABSTRACT

A breakthrough study from Du et al. has developed a wearable, ultrasound imaging patch for standardized and reproducible breast tissue imaging. The technology utilizes a honeycomb patch design to facilitate guided movement of the ultrasound array, enabling comprehensive, multiangle breast imaging. The system was validated in vitro and in vivo with a single human subject and has the potential for early-stage breast cancer detection. This study addressed the current limitations of wearable ultrasound technologies, including imaging over large, curvilinear organs and integration of superior piezoelectric materials for high-performance ultrasound arrays. The transition of ultrasound from the bedside to portable and wearable devices will pave the way for integration with big data collection, such as artificial intelligence (AI)-based diagnosis and personalized ultrasonographic profile generation, for rapid and objective measurements. This advancement is especially important in the context of breast cancer, where early diagnosis and assessment of medical therapy responses are paramount to patient care.


Subject(s)
Breast Neoplasms , Wearable Electronic Devices , Humans , Female , Artificial Intelligence , Diagnostic Imaging , Ultrasonography , Breast Neoplasms/diagnostic imaging
5.
J Neurosci ; 43(34): 5989-5995, 2023 08 23.
Article in English | MEDLINE | ID: mdl-37612141

ABSTRACT

The brain is a complex system comprising a myriad of interacting neurons, posing significant challenges in understanding its structure, function, and dynamics. Network science has emerged as a powerful tool for studying such interconnected systems, offering a framework for integrating multiscale data and complexity. To date, network methods have significantly advanced functional imaging studies of the human brain and have facilitated the development of control theory-based applications for directing brain activity. Here, we discuss emerging frontiers for network neuroscience in the brain atlas era, addressing the challenges and opportunities in integrating multiple data streams for understanding the neural transitions from development to healthy function to disease. We underscore the importance of fostering interdisciplinary opportunities through workshops, conferences, and funding initiatives, such as supporting students and postdoctoral fellows with interests in both disciplines. By bringing together the network science and neuroscience communities, we can develop novel network-based methods tailored to neural circuits, paving the way toward a deeper understanding of the brain and its functions, as well as offering new challenges for network science.


Subject(s)
Neurosciences , Humans , Brain , Drive , Neurons , Research Personnel
6.
ArXiv ; 2023 May 11.
Article in English | MEDLINE | ID: mdl-37214134

ABSTRACT

The brain is a complex system comprising a myriad of interacting elements, posing significant challenges in understanding its structure, function, and dynamics. Network science has emerged as a powerful tool for studying such intricate systems, offering a framework for integrating multiscale data and complexity. Here, we discuss the application of network science in the study of the brain, addressing topics such as network models and metrics, the connectome, and the role of dynamics in neural networks. We explore the challenges and opportunities in integrating multiple data streams for understanding the neural transitions from development to healthy function to disease, and discuss the potential for collaboration between network science and neuroscience communities. We underscore the importance of fostering interdisciplinary opportunities through funding initiatives, workshops, and conferences, as well as supporting students and postdoctoral fellows with interests in both disciplines. By uniting the network science and neuroscience communities, we can develop novel network-based methods tailored to neural circuits, paving the way towards a deeper understanding of the brain and its functions.

7.
Ultrasound Med Biol ; 48(5): 743-759, 2022 05.
Article in English | MEDLINE | ID: mdl-35125244

ABSTRACT

Ultrasound localization microscopy (ULM) is an emerging, super-resolution imaging technique for detailed mapping of the microvascular structure and flow velocity via subwavelength localization and tracking of microbubbles. Because microbubbles rely on blood flow for movement throughout the vascular space, acquisition times can be long in the smallest, low-flow microvessels. In addition, detection of microbubbles in low-flow regions can be difficult because of minimal separation of microbubble signal from tissue. Nanoscale, phase-change contrast agents (PCCAs) have emerged as a switchable, intermittent or persisting contrast agent for ULM via acoustic droplet vaporization (ADV). Here, the focus is on characterizing the spatiotemporal contrast properties of less volatile perfluoropentane (PFP) PCCAs. The results indicate that at physiological temperature, nanoscale PFP PCCAs with diameters less than 100 nm disappear within microseconds after ADV with high-frequency ultrasound (16 MHz, 5- to 6-MPa peak negative pressure) and that nanoscale PFP PCCAs have an inherent deactivation mechanism via immediate recondensation after ADV. This "blinking" on-and-off contrast signal allowed separation of flow in an in vitro flow phantom, regardless of flow conditions, although with a need for some replenishment at very low flow conditions to maintain count rate. This blinking behavior allows for rapid spatial mapping in areas of low or no flow with ULM, but limits velocity tracking because there is no stable bubble formation with nanoscale PFP PCCAs.


Subject(s)
Fluorocarbons , Microscopy , Contrast Media/chemistry , Fluorocarbons/chemistry , Microbubbles , Ultrasonography/methods
8.
Medicina (Kaunas) ; 58(1)2022 Jan 01.
Article in English | MEDLINE | ID: mdl-35056374

ABSTRACT

Background and Objectives: Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. Acute exacerbations (AECOPD) are common and often triggered by viral infection. During the COVID-19 pandemic social restrictions, including 'shielding' and 'lockdowns', were mandated. Multiple, worldwide studies report a reduction in AECOPD admissions during this period. This study aims to assess the effect of the pandemic and Lockdown on the rates of admission with AECOPD and severity of hospitalised exacerbations in the North-East of England. Materials and Methods: Data were extracted for patients presenting with a diagnosis of AECOPD or respiratory failure secondary to AECOPD during the 'COVID-19 period' (26/3/20-31/12/20) and a date-matched control period from the year previous. We present descriptive statistics and regression analysis of the effects of the COVID-19 period on the rates of hospital admission. Results: Compared to the matched control period, the COVID-19 period was associated with fewer AECOPD admissions (COVID-19 = 719, control = 1257; rate ratio 0.57, p < 0.001) and shorter length of stay (COVID-19 = 3.9 ± 0.2, control = 4.78 ± 0.2 days; p = 0.002), with similar in-hospital plus 30-day post-discharge mortality. Demographics were similar between periods. Only six patients had a positive COVID-19 PCR test. Conclusion: During the COVID-19 period there was a substantial reduction in AECOPD admissions, but no increase in overall severity of exacerbations or mortality. Rather than fear driving delayed hospital presentation, physical and behavioural measures taken during this period to limit transmission of COVID-19 are likely to have reduced transmission of other respiratory viruses. This has important implications for control of future AECOPD.


Subject(s)
COVID-19 , Pulmonary Disease, Chronic Obstructive , Aftercare , Communicable Disease Control , Hospitals , Humans , Pandemics , Patient Discharge , Pulmonary Disease, Chronic Obstructive/epidemiology , Pulmonary Disease, Chronic Obstructive/therapy , SARS-CoV-2
9.
Article in English | MEDLINE | ID: mdl-35020595

ABSTRACT

Elevated intraocular pressure (IOP) is the most prevalent risk factor for initiation and progression of neurodegeneration in glaucoma. Ocular hypertension results from increased resistance to aqueous fluid outflow caused by reduced porosity and increased stiffness of tissues of the outflow pathway. Acoustic activation and resulting bioeffects of the perfluorocarbon (PFC) nanodroplets (NDs) introduced into the anterior chamber (AC) of the eye could potentially represent a treatment for glaucoma by increasing permeability in the aqueous outflow track. To evaluate the potential of NDs to enter the outflow track, 100-nm diameter perfluoropentane (PFP) NDs with a lipid shell were injected into the AC of ex vivo pig eyes and in vivo rat eyes. The NDs were activated and imaged with 18- and 28-MHz linear arrays to assess their location and diffusion. NDs in the AC could also be visualized using optical coherence tomography (OCT). Because of their higher density with respect to aqueous humor, some NDs settled into the iridocorneal angle where they entered the outflow pathway. After acoustic activation of the NDs at the highest acoustic pressure, small gas bubbles were observed in the AC. After two days, no acoustic activation events were visible in the AC of the rats and their eyes showed no evidence of inflammation.


Subject(s)
Fluorocarbons , Glaucoma , Animals , Aqueous Humor/metabolism , Glaucoma/diagnostic imaging , Glaucoma/metabolism , Intraocular Pressure , Rats , Swine , Ultrasonography
10.
J Control Release ; 337: 458-471, 2021 09 10.
Article in English | MEDLINE | ID: mdl-34324895

ABSTRACT

Focused ultrasound (FUS) in combination with systemically injected microbubbles can be used to non-invasively open the blood-brain barrier (BBB) in targeted regions for a variety of therapeutic applications. Over the past two decades, preclinical research into the safety and efficacy of FUS-induced BBB opening has proven this technique to be transient and efficacious, propelling FUS-induced BBB opening into several clinical trials in recent years. However, as clinical trials further progress, the neuroinflammatory response to FUS-induced BBB opening needs to be better understood. In this study, we provide further insight into the relationship of microbubble cavitation and the resulting innate immune response to FUS-induced BBB opening. By keeping ultrasound parameters fixed (i.e. frequency, pressure, pulse length, etc.), three groups of mice were sonicated using a real-time cavitation controller until a target cavitation dose was reached (1 x 107 V2•s, 5 x 107 V2•s, 1 x 108 V2•s). The change in relative gene expression of the mouse inflammatory cytokines and receptors were evaluated at three different time-points (6 h, 24 h, and 72 h) after FUS. At both 6 and 24 h time-points, significant changes in relative gene expression of inflammatory cytokines and receptors were observed across all cavitation groups. However, the degree of changes in relative expression levels and the number of genes with significant changes in expression varied across the cavitation groups. Groups with a higher cavitation dose exhibited both greater changes in relative expression levels and greater number of significant changes. By 72 h post-opening, the gene expression levels returned to baseline in all cavitation dose groups, signifying a transient inflammatory response to FUS-induced BBB opening at the targeted cavitation dose levels. Furthermore, the real-time cavitation controller was able to produce consistent and significantly different BBB permeability enhancement volumes across the three different cavitation dose groups. These results indicate that cavitation monitoring and controlling during FUS-induced BBB opening can be used to potentially modulate or limit the degree of neuroinflammation, further emphasizing the importance of implementing cavitation controllers as FUS-induced BBB opening is translated into the clinic.


Subject(s)
Blood-Brain Barrier , Inflammation , Sonication/methods , Animals , Drug Delivery Systems , Magnetic Resonance Imaging , Mice , Microbubbles , Permeability , Sonication/adverse effects
11.
Sci Rep ; 11(1): 15043, 2021 07 22.
Article in English | MEDLINE | ID: mdl-34294761

ABSTRACT

An emerging approach with potential in improving the treatment of neurodegenerative diseases and brain tumors is the use of focused ultrasound (FUS) to bypass the blood-brain barrier (BBB) in a non-invasive and localized manner. A large body of pre-clinical work has paved the way for the gradual clinical implementation of FUS-induced BBB opening. Even though the safety profile of FUS treatments in rodents has been extensively studied, the histological and behavioral effects of clinically relevant BBB opening in large animals are relatively understudied. Here, we examine the histological and behavioral safety profile following localized BBB opening in non-human primates (NHPs), using a neuronavigation-guided clinical system prototype. We show that FUS treatment triggers a short-lived immune response within the targeted region without exacerbating the touch accuracy or reaction time in visual-motor cognitive tasks. Our experiments were designed using a multiple-case-study approach, in order to maximize the acquired data and support translation of the FUS system into human studies. Four NHPs underwent a single session of FUS-mediated BBB opening in the prefrontal cortex. Two NHPs were treated bilaterally at different pressures, sacrificed on day 2 and 18 post-FUS, respectively, and their brains were histologically processed. In separate experiments, two NHPs that were earlier trained in a behavioral task were exposed to FUS unilaterally, and their performance was tracked for at least 3 weeks after BBB opening. An increased microglia density around blood vessels was detected on day 2, but was resolved by day 18. We also detected signs of enhanced immature neuron presence within areas that underwent BBB opening, compared to regions with an intact BBB, confirming previous rodent studies. Logistic regression analysis showed that the NHP cognitive performance did not deteriorate following BBB opening. These preliminary results demonstrate that neuronavigation-guided FUS with a single-element transducer is a non-invasive method capable of reversibly opening the BBB, without substantial histological or behavioral impact in an animal model closely resembling humans. Future work should confirm the observations of this multiple-case-study work across animals, species and tasks.


Subject(s)
Blood-Brain Barrier/metabolism , Blood-Brain Barrier/radiation effects , Neuronavigation/methods , Ultrasonic Waves , Animals , Behavior, Animal , Biological Transport/radiation effects , Biomarkers , Blood-Brain Barrier/diagnostic imaging , Cognition , Magnetic Resonance Imaging , Microbubbles , Models, Animal , Primates , Quantitative Trait, Heritable
12.
Ultrasound Med Biol ; 47(8): 2360-2376, 2021 08.
Article in English | MEDLINE | ID: mdl-34023187

ABSTRACT

Bulk ultrasound ablation is a thermal therapy approach in which tissue is heated by unfocused or weakly focused sonication (average intensities on the order of 100 W/cm2) to achieve coagulative necrosis within a few minutes exposure time. Assessing the role of bubble activity, including acoustic cavitation and tissue vaporization, in bulk ultrasound ablation may help in making bulk ultrasound ablation safer and more effective for clinical applications. Here, two series of ex vivo ablation trials were conducted to investigate the role of bubble activity and tissue vaporization in bulk ultrasound ablation. Fresh bovine liver tissue was ablated with unfocused, continuous-wave ultrasound using ultrasound image-ablate arrays sonicating at 31 W/cm2 (0.9 MPa amplitude) for either 20 min at a frequency of 3.1 MHz or 10 min at 4.8 MHz. Tissue specimens were maintained at a static overpressure of either 0.52 or 1.2 MPa to suppress bubble activity and tissue vaporization or at atmospheric pressure for control groups. A passive cavitation detector was used to record subharmonic (1.55 or 2.4 MHz), broadband (1.2-1.5 MHz) and low-frequency (5-20 kHz) acoustic emissions. Treated tissue was stained with 2% triphenyl tetrazolium chloride to evaluate thermal lesion dimensions. Subharmonic emissions were significantly reduced in overpressure groups compared with control groups. Correlations observed between acoustic emissions and lesion dimensions were significant and positive for the 3.1-MHz series, but significant and negative for the 4.8-MHz series. The results indicate that for bulk ultrasound ablation, where both acoustic cavitation and tissue vaporization are possible, bubble activity can enhance ablation in the absence of tissue vaporization, but can reduce thermal lesion dimensions in the presence of vaporization.


Subject(s)
High-Intensity Focused Ultrasound Ablation , Pressure , Sonication , Volatilization , Acoustics , Animals , Cattle
13.
IEEE Trans Med Imaging ; 39(11): 3391-3402, 2020 11.
Article in English | MEDLINE | ID: mdl-32406828

ABSTRACT

Focused ultrasound (FUS) is an emerging technique for neuromodulation due to its noninvasive application and high depth penetration. Recent studies have reported success in modulation of brain circuits, peripheral nerves, ion channels, and organ structures. In particular, neuromodulation of peripheral nerves and the underlying mechanisms remain comparatively unexplored in vivo. Lack of methodologies for FUS targeting and monitoring impede further research in in vivo studies. Thus, we developed a method that non-invasively measures nerve engagement, via tissue displacement, during FUS neuromodulation of in vivo nerves using simultaneous high frame-rate ultrasound imaging. Using this system, we can validate, in real-time, FUS targeting of the nerve and characterize subsequent compound muscle action potentials (CMAPs) elicited from sciatic nerve activation in mice using 0.5 to 5 ms pulse durations and 22 - 28 MPa peak positive stimulus pressures at 4 MHz. Interestingly, successful motor excitation from FUS neuromodulation required a minimum interframe nerve displacement of 18 µm without any displacement incurred at the skin or muscle levels. Moreover, CMAPs detected in mice monotonically increased with interframe nerve displacements within the range of 18 to 300 µm . Thus, correlation between nerve displacement and motor activation constitutes strong evidence FUS neuromodulation is driven by a mechanical effect given that tissue deflection is a result of highly focused acoustic radiation force.


Subject(s)
Peripheral Nerves , Ultrasonic Therapy , Animals , Mice , Peripheral Nerves/diagnostic imaging , Ultrasonography
14.
Ultrasound Med Biol ; 46(1): 73-89, 2020 01.
Article in English | MEDLINE | ID: mdl-31668690

ABSTRACT

Focused ultrasound (FUS)-mediated blood-brain barrier (BBB) opening is currently being investigated in clinical trials. Here, we describe a portable clinical system with a therapeutic transducer suitable for humans, which eliminates the need for in-line magnetic resonance imaging (MRI) guidance. A neuronavigation-guided 0.25-MHz single-element FUS transducer was developed for non-invasive clinical BBB opening. Numerical simulations and experiments were performed to determine the characteristics of the FUS beam within a human skull. We also validated the feasibility of BBB opening obtained with this system in two non-human primates using U.S. Food and Drug Administration (FDA)-approved treatment parameters. Ultrasound propagation through a human skull fragment caused 44.4 ± 1% pressure attenuation at a normal incidence angle, while the focal size decreased by 3.3 ± 1.4% and 3.9 ± 1.8% along the lateral and axial dimension, respectively. Measured lateral and axial shifts were 0.5 ± 0.4 mm and 2.1 ± 1.1 mm, while simulated shifts were 0.1 ± 0.2 mm and 6.1 ± 2.4 mm, respectively. A 1.5-MHz passive cavitation detector transcranially detected cavitation signals of Definity microbubbles flowing through a vessel-mimicking phantom. T1-weighted MRI confirmed a 153 ± 5.5 mm3 BBB opening in two non-human primates at a mechanical index of 0.4, using Definity microbubbles at the FDA-approved dose for imaging applications, without edema or hemorrhage. In conclusion, we developed a portable system for non-invasive BBB opening in humans, which can be achieved at clinically relevant ultrasound exposures without the need for in-line MRI guidance. The proposed FUS system may accelerate the adoption of non-invasive FUS-mediated therapies due to its fast application, low cost and portability.


Subject(s)
Blood-Brain Barrier/diagnostic imaging , Neuronavigation/methods , Transducers , Animals , Equipment Design , Humans , Neuronavigation/instrumentation , Primates , Ultrasonography
15.
Inorg Chem ; 58(23): 15801-15811, 2019 Dec 02.
Article in English | MEDLINE | ID: mdl-31714068

ABSTRACT

O2 activation at nonheme iron centers is a common motif in biological systems. While synthetic models have provided numerous insights into the reactivity of high-valent iron-oxo complexes related to biological processes, the majority of these complexes are synthesized using alternative oxidants. This report describes O2 activation by an iron(II)-triflate complex of the imino-functionalized tris(pyrrol-2-ylmethyl)amine ligand framework, H3[N(piCy)3]. Initial reaction conditions result in the formation of a mixture of oxidation products including terminal iron(III)-oxo and iron(III)-hydroxo complexes. The relevance of these species to the O2 activation process is demonstrated through reactivity studies and electrochemical analysis of the iron(III)-oxo complex.

16.
J Acoust Soc Am ; 146(2): EL158, 2019 08.
Article in English | MEDLINE | ID: mdl-31472567

ABSTRACT

Characterization of ultrasound fields is a routine procedure for both diagnostic and therapeutic ultrasound. Quantitative field mapping with a calibrated hydrophone and multi-axis positioning system can be difficult and time consuming. In this study, the use of acoustic cavitation field mapping as a qualitative surrogate to acoustic pressure field mapping, albeit without acoustic pressure values is demonstrated. This technique allows for fast qualitative mapping of ultrasound fields and thereby functionality of the corresponding transducers, in a matter of seconds. In addition, this technique could be used to rapidly image in vivo acoustic cavitation fields during therapeutic ultrasound applications.


Subject(s)
Ultrasonography/methods , Contrast Media , Microbubbles , Transducers , Ultrasonic Waves , Ultrasonography/instrumentation
17.
Psychol Health ; 34(12): 1451-1469, 2019 12.
Article in English | MEDLINE | ID: mdl-31111737

ABSTRACT

Objectives: Government guidelines aim to promote sensible alcohol consumption but such advice is disconnected from people's lived experiences. This research investigated how people construct personal thresholds of 'too much' alcohol. Design and measures: One hundred fifty drinkers completed an online survey (Mage = 23.29(5.51); 64.7% female). Participants were asked whether they had an intuitive sense of what constitutes too much alcohol. They wrote open-ended descriptions of how that threshold had been established and how it felt to approach/exceed it. These qualitative accounts were coded using thematic analysis and interpreted with an experiential theoretical framework. Results: Personal thresholds were based on previously experienced embodied states rather than guidelines, or health concerns. Describing the approach to their threshold, 75% of participants fell into two distinct groups. Group 1's approach was an entirely negative embodied experience (nausea/anxiety) and Group 2's approach was an entirely positive, embodied experience (relaxed/pleasurable). These groups differed significantly in awareness of alcohol's effects, agency and self-perceptions, but not on alcohol consumption. Exceeding their threshold was an entirely negative embodied experience for all. Conclusion: These findings illustrate that people are guided by experientially grounded conceptions of consumption. Interventions could target different groups of drinker according to their embodied experience during the approach to 'too much' alcohol.


Subject(s)
Alcohol Drinking/adverse effects , Adult , Female , Humans , Male , Surveys and Questionnaires , Young Adult
18.
PeerJ ; 7: e6759, 2019.
Article in English | MEDLINE | ID: mdl-31024767

ABSTRACT

BACKGROUND: The eggs of head lice are fixed to the hair of their hosts by means of a persistent glue-like fixative that is not chemically bound to the substrate. Eggshells stuck to hairs after successfully treating the infestation are a cosmetic issue and a source of misunderstanding about whether the infestation is eliminated. Hitherto, no effective treatment to loosen louse eggs and nits has been found. METHODS: An extensive screening of surface active compounds, oils, esters, and other cosmetic lubricants used a slip-peel device to measure the forces required to release the grip of the fixative. Promisingly effective compounds were formulated into suitable carriers for further testing. The most effective combination formulation was tested, as a commercial product (Hedrin Stubborn Egg Loosening Lotion), in a usage study of 15 children with nits, in which one half of the head was combed only on damp hair and the other half combed after a 10 min treatment using the product. RESULTS: Laboratory tests of the forces required to remove nits found that pelagonic acid derivatives, particularly isononyl isononanoate, in the presence of a polymeric gelling agent and water, were most effective to reduce the initial grip of the fixative as well as reducing friction as the eggshell is drawn along the hair shaft and that the final product was significantly (p < 0.05) more effective than several other marketed materials. In the usage study significantly (p = 0.01046) more louse eggs and nits were removed after treatment with the gel. DISCUSSION: The product developed through this study is the first with a demonstrable efficacy for loosening the grip of the louse egg fixative from hair. Consequently, until now, and despite the availability of effective pediculicidal treatments, dealing with the eggshells persisting after an infestation has been an onerous task for most households. This type of product can enable families to deal more easily with persistent eggshells and improve self-esteem in affected children.

19.
Ultrasound Med Biol ; 45(3): 846-858, 2019 03.
Article in English | MEDLINE | ID: mdl-30638968

ABSTRACT

Acoustic cavitation can be used to temporarily disrupt cell membranes for intracellular delivery of large biomolecules. Termed sonoporation, the ability of this technique for efficient intracellular delivery (i.e., >50% of initial cell population showing uptake) while maintaining cell viability (i.e., >50% of initial cell population viable) has proven to be very difficult. Here, we report that phase-shift nanoemulsions (PSNEs) function as inertial cavitation nuclei for improvement of sonoporation efficiency. The interplay between ultrasound frequency, resultant microbubble dynamics and sonoporation efficiency was investigated experimentally. Acoustic emissions from individual microbubbles nucleated from PSNEs were captured using a broadband passive cavitation detector during and after acoustic droplet vaporization with short pulses of ultrasound at 1, 2.5 and 5 MHz. Time domain features of the passive cavitation detector signals were analyzed to estimate the maximum size (Rmax) of the microbubbles using the Rayleigh collapse model. These results were then applied to sonoporation experiments to test if uptake efficiency is dependent on maximum microbubble size before inertial collapse. Results indicated that at the acoustic droplet vaporization threshold, Rmax was approximately 61.7 ± 5.2, 24.9 ± 2.8, and 12.4 ± 2.1 µm at 1, 2.5 and 5 MHz, respectively. Sonoporation efficiency increased at higher frequencies, with efficiencies of 39.5 ± 13.7%, 46.6 ± 3.28% and 66.8 ± 5.5% at 1, 2.5 and 5 MHz, respectively. Excessive cellular damage was seen at lower frequencies because of the erosive effects of highly energetic inertial cavitation. These results highlight the importance of acoustic cavitation control in determining the outcome of sonoporation experiments. In addition, PSNEs may serve as tailorable inertial cavitation nuclei for other therapeutic ultrasound applications.


Subject(s)
Cell Membrane Permeability/physiology , Microbubbles , Nanoparticles , Sonication/methods , Acoustics , Cell Membrane , Emulsions
20.
BMC Cancer ; 18(1): 1284, 2018 Dec 22.
Article in English | MEDLINE | ID: mdl-30577821

ABSTRACT

BACKGROUND: Cisplatin has been widely used for the treatment of cancer and its antitumour activity is attributed to its capacity to form DNA adducts, predominantly at guanine residues, which impede cellular processes such as DNA replication and transcription. However, there are associated toxicity and drug resistance issues which plague its use. This has prompted the development and screening of a range of chemotherapeutic drug analogues towards improved efficacy. The biological properties of three novel platinum-based compounds consisting of varying cis-configured ligand groups, as well as a commercially supplied compound, were characterised in this study to determine their potential as anticancer agents. METHODS: The linear amplification reaction was employed, in conjunction with capillary electrophoresis, to quantify the sequence specificity of DNA adducts induced by these compounds using a DNA template containing telomeric repeat sequences. Additionally, the DNA interstrand cross-linking and unwinding efficiency of these compounds were assessed through the application of denaturing and native agarose gel electrophoresis techniques, respectively. Their cytotoxicity was determined in HeLa cells using a colorimetric cell viability assay. RESULTS: All three novel platinum-based compounds were found to induce DNA adduct formation at the tandem telomeric repeat sequences. The sequence specificity profile at these sites was characterised and these were distinct from that of cisplatin. Two of these compounds with the enantiomeric 1,2-diaminocyclopentane ligand (SS and RR-DACP) were found to induce a greater degree of DNA unwinding than cisplatin, but exhibited marginally lower DNA cross-linking efficiencies. Furthermore, the RR-isomer was more cytotoxic in HeLa cells than cisplatin. CONCLUSIONS: The biological characteristics of these compounds were assessed relative to cisplatin, and a variation in the sequence specificity and a greater capacity to induce DNA unwinding was observed. These compounds warrant further investigations towards developing more efficient chemotherapeutic drugs.


Subject(s)
DNA Adducts/drug effects , DNA/drug effects , Neoplasms/drug therapy , Organoplatinum Compounds/chemistry , Cisplatin/analogs & derivatives , Cisplatin/chemistry , Cisplatin/therapeutic use , Cross-Linking Reagents , DNA/chemistry , DNA Damage/drug effects , HeLa Cells , Humans , Nucleic Acid Conformation/drug effects , Organoplatinum Compounds/therapeutic use , Platinum/chemistry , Platinum/therapeutic use , Stereoisomerism
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