High frequency acoustic nebulization for pulmonary delivery of antibiotic alternatives against Staphylococcus aureus.

The increasing prevalence of multidrug resistant bacteria has warranted the search for new antimicrobial agents as existing antibiotics lose their potency. Among these, bacteriophage therapy, as well as the administration of specific bacteriolysis agents, i.e., lytic enzymes, have emerged as attractive alternatives. Nebulizers offer the possibility for delivering these therapeutics directly to the lung, which is particularly advantageous as a non-invasive and direct route to treat bacterial lung infections. Nevertheless, nebulizers can often result in significant degradation of the bacteriophage or protein, both structurally and functionally, due to the large stresses the aerosolization process imposes on these entities. In this work, we assess the capability of a novel low-cost and portable hybrid surface and bulk acoustic wave platform (HYDRA) to nebulize a Myoviridae bacteriophage (phage K) and lytic enzyme (lysostaphin) that specifically targets Staphylococcus aureus. Besides its efficiency in producing phage or protein-laden aerosols within the 1-5 µm respirable range for optimum delivery to the lower respiratory tract where lung infections commonly take place, we observe that the HYDRA platform-owing to the efficiency of driving the aerosolization process at relatively low powers and high frequencies (approximately 10 MHz)-does not result in appreciable denaturation of the phages or proteins, such that the loss of antimicrobial activity following nebulization is minimized. Specifically, a low (0.1 log10 (pfu/ml)) titer loss was obtained with the phages, resulting in a high viable respirable fraction of approximately 90%. Similarly, minimal loss of antimicrobial activity was obtained with lysostaphin upon nebulization wherein its minimum inhibitory concentration (0.5 µg/ml) remained unaltered as compared with the non-nebulized control. These results therefore demonstrate the potential of the HYDRA nebulization platform as a promising strategy for pulmonary administration of alternative antimicrobial agents to antibiotics for the treatment of lung diseases caused by pathogenic bacteria.

On-Chip Generation of Vortical Flows for Microfluidic Centrifugation.

Microcentrifugation constitutes an important part of the microfluidic toolkit in a similar way that centrifugation is crucial to many macroscopic procedures, given that micromixing, sample preconcentration, particle separation, component fractionation, and cell agglomeration are essential operations in small scale processes. Yet, the dominance of capillary and viscous effects, which typically tend to retard flow, over inertial and gravitational forces, which are often useful for actuating flows and hence centrifugation, at microscopic scales makes it difficult to generate rotational flows at these dimensions, let alone with sufficient vorticity to support efficient mixing, separation, concentration, or aggregation. Herein, the various technologies-both passive and active-that have been developed to date for vortex generation in microfluidic devices are reviewed. Various advantages or limitations associated with each are outlined, in addition to highlighting the challenges that need to be overcome for their incorporation into integrated microfluidic devices.

Lamb to Rayleigh Wave Conversion on Superstrates as a Means to Facilitate Disposable Acoustomicrofluidic Applications.

Rayleigh surface acoustic waves (SAWs) have been demonstrated as a powerful and effective means for driving a wide range of microfluidic actuation processes. Traditionally, SAWs have been generated on piezoelectric substrates, although the cost of the material and the electrode deposition process makes them less amenable as low-cost and disposable components. As such, a "razor-and-blades" model that couples the acoustic energy of the SAW on the piezoelectric substrate through a fluid coupling layer and into a low-cost and, hence, disposable silicon superstrate on which various microfluidic processes can be conducted has been proposed. Nevertheless, it was shown that only bulk vibration in the form of Lamb waves can be excited in the superstrate, which is considerably less efficient and flexible in terms of microfluidic functionality compared to its surface counterpart, that is, the SAW. Here, we reveal an extremely simple way that quite unexpectedly and rather nonintuitively allows SAWs to be generated on the superstrate-by coating the superstrate with a thin gold layer. In addition to verifying the existence of the SAW on the coated superstrate, we carry out finite-difference time domain numerical simulations that not only confirm the experimental observations but also facilitate an understanding of the surprising difference that the coating makes. Finally, we elucidate the various power-dependent particle concentration phenomena that can be carried out in a sessile droplet atop the superstrate and show the possibility for simply carrying out rapid and effective microcentrifugation-a process that is considerably more difficult with Lamb wave excitation on the superstrate.

Acoustically Driven Micromixing: Effect of Transducer Geometry.

The ability to drive efficient micromixing on a microfluidic platform is crucial for a wide range of lab-on-a-chip applications. Here, we investigate the ability of acoustic waves generated on different geometric surfaces (concave and convex) to enhance the micromixing efficiency in droplet acoustomicrofluidic systems, and, concomitantly, to reduce the power consumption in these devices for a given performance requirement. Quite counterintuitively, we observe that although the acoustic streaming velocity, which scaled inversely with the droplet size, tended to be generally lower (by approximately 45%) when the flow is generated by transducers with convex surfaces compared to those with concave surfaces, the mixing efficiency is disproportionately higher: compared to pure diffusional mixing in the absence of the acoustic forcing, the mixing efficiency due to the acoustically driven convection increased by up to 25% and 43% on these respective surfaces. As such, the mixing enhancement cannot simply be attributed to an increase in the convective flow arising from the acoustic forcing. Rather, we observe the mixing enhancement to be due to the stronger chaotic advection arising in the transducer with the convex surface due to its diverging acoustic field into the droplet.

Exploring New Applications of Lysozyme-Shelled Microbubbles.

This feature article provides a review of recent work on the synthesis of biopolymer-shelled microbubbles using various techniques with a particular focus on ultrasonic methodology that offers advantages over other conventional methods for tuning their physical and functional properties. A detailed discussion on the role of surface chemistry in fabricating functional lysozyme-shelled microbubbles has also been presented. Highlights on the applications of lysozyme-shelled microbubbles, particularly recent findings on their use for potential theranostic applications in lung diseases, have also been presented.

Acoustomicrofluidic assembly of oriented and simultaneously activated metal-organic frameworks.

The high surface area and porosity, and limitless compound and network combinations between the metal ions and organic ligands making up metal-organic frameworks (MOFs) offer tremendous opportunities for their use in many applications. While numerous methods have been proposed for the synthesis of MOF powders, it is often difficult to obtain oriented crystals with these techniques. Further, the need for additional post-synthesis steps to activate the crystals and release them from the substrate presents a considerable production challenge. Here, we report an acoustically-driven microcentrifugation platform that facilitates fast convective solutal transport, allowing the synthesis of MOF crystals in as short as five minutes. The crystals are not only oriented due to long-range out-of-plane superlattice ordering aided by molecular dipole polarization under the acoustoelectric coupling, but also simultaneously activated during the synthesis process.

Enhancing rate of water absorption in seeds via a miniature surface acoustic wave device.

Seeds, which are high in protein and essential nutrients, must go through a hydration process before consumption. The ability to rapidly increase water absorption can significantly reduce the soaking time as well as the amount of energy needed for cooking seeds. Many studies in the literature employ high-power (102 W) low-frequency (104 Hz) ultrasound; although their results are very promising where more than 100% increase in water content can be obtained between the treated and untreated seeds, the high-power and low-frequency ultrasound often causes acoustic cavitation under high intensity, which can severely disrupt the cell walls and damage the seeds. In our study, however, we demonstrate that treating the seeds via a miniature surface acoustic wave device, which operates at low-power (100 W) and high-frequency (107 Hz) range, gives rise to a higher water absorption rate without the acoustic cavitations. By comparing the water content between the treated and untreated seeds, an increase of up to 2600% (for chickpeas) and 6350% (for mung bean) can be obtained after 60 min. A significantly higher water absorption in mung beans can be attributed to the larger pore size when compared with the acoustic wavelength in water, enabling an efficient transmission of acoustic wave inside the pores. Our results also indicate that the germination time can be reduced by half for treated seeds as compared to the untreated seeds.

Hybrid Surface and Bulk Resonant Acoustics for Concurrent Actuation and Sensing on a Single Microfluidic Device.

While many microfluidic devices have been developed for sensing and others for actuation, few devices can perform both tasks effectively and simultaneously on the same platform. In piezoelectric sensors and actuators, this is due to the opposing operating requirements for sensing and actuation. Sensing ideally requires narrow resonant peaks characterized by high quality factors, such as those found in quartz crystals. However, these materials usually have poor electromechanical coupling coefficients that are not ideal for actuation. In this work, we show that it is possible to achieve both sensing and actuation simultaneously on a shared device by exploiting the distinct advantages of both bulk waves for effective mass sensing and surface waves for highly efficient microfluidic actuation through a unique hybrid surface and bulk acoustic wave platform. In light of the recent resurgence of interest in portable inhaled insulin devices for personalized diabetes management, we demonstrate the use of this technology for efficient aerosolization of insulin for inhalation without denaturing the protein, while being able to concurrently detect the residual mass of the un-nebulized insulin remaining on the device such that the actual dose delivered to the patient can be determined in real time.

Increased insula-putamen connectivity in X-linked dystonia-parkinsonism.

Preliminary evidence from postmortem studies of X-linked dystonia-parkinsonism (XDP) suggests tissue loss may occur first and/or most severely in the striatal striosome compartment, followed later by cell loss in the matrix compartment. However, little is known about how this relates to pathogenesis and pathophysiology. While MRI cannot visualize these striatal compartments directly in humans, differences in relative gradients of afferent cortical connectivity across compartments (weighted toward paralimbic versus sensorimotor cortex, respectively) can be used to infer potential selective loss in vivo. In the current study we evaluated relative connectivity of paralimbic versus sensorimotor cortex with the caudate and putamen in 17 individuals with XDP and 17 matched controls. Although caudate and putamen volumes were reduced in XDP, there were no significant reductions in either "matrix-weighted", or "striosome-weighted" connectivity. In fact, paralimbic connectivity with the putamen was elevated, rather than reduced, in XDP. This was driven most strongly by elevated putamen connectivity with the anterior insula. There was no relationship of these findings to disease duration or striatal volume, suggesting insula and/or paralimbic connectivity in XDP may develop abnormally and/or increase in the years before symptom onset.

The Basal Ganglia Striosomes Affect the Modulation of Conflicts by Subliminal Information-Evidence from X-Linked Dystonia Parkinsonism.

Cognitive control is relevant when distracting information induces behavioral conflicts. Such conflicts can be produced consciously and by subliminally processed information. Interestingly, both sources of conflict interact suggesting that they share neural mechanisms. Here, we ask whether conjoint effects between different sources of conflict are modulated by microstructural basal ganglia dysfunction. To this end, we carried out an electroencephalography study and examined event-related potentials (ERPs) including source localization using a combined flanker-subliminal priming task in patients with X-linked dystonia Parkinsonism (XDP) and a group of healthy controls. XDP in its early stages is known to predominantly affect the basal ganglia striosomes. The results suggest that conjoint effects between subliminal and conscious sources of conflicts are modulated by the striosomes and were stronger in XDP patients. The neurophysiological data indicate that this effect is related to modulations in conflict monitoring and response selection (N2 ERP) mechanisms engaging the anterior cingulate cortex. Bottom-up perceptual gating, attentional selection, and motor response activation processes in response to the stimuli (P1, N1, and lateralized readiness potential ERPs) were unaffected. Taken together, these data indicate that striosomes modulate the processing of conscious and subliminal sources of conflict suggesting that microstructural basal ganglia properties are relevant for cognitive control.

Accuracy and reproducibility of the Etest to detect drug-resistant Neisseria gonorrhoeae to contemporary treatment.

PURPOSE: Neisseria gonorrhoeae is a sexually transmitted bacterial pathogen that continues to evolve to become resistant to known antibiotics. In preparing for potential emergence, the Centers for Disease Control and Prevention recommends that clinical laboratories maintain or develop protocols to assess antibiotic susceptibly for this organism. This study examines the intra-laboratory variability of using the Etest method to provide consistent MIC values for N. gonorrhoeae and also compared the results of the Etest to known agar dilution MIC values. METHODOLOGY: Clinical N. gonorrhoeae isolates, 100 paired duplicates, were tested by eight laboratories for antibiotic susceptibility to ceftriaxone, cefixime and azithromycin using Etest strips.Results/Key findings. Overall, >80 % of the paired Etest MIC values were within one log2 dilution of the replicate. When compared to the agar dilution reference method, the cefixime Etest MIC values were consistently underreported by one dilution (seven laboratories) or two dilutions (one laboratory). The azithromycin Etest MIC values agreed 90.7 % with the agar dilution MIC values while the agreement with ceftriaxone was 90.9 %. CONCLUSION: Overall, the Etest method yielded reproducible MIC values within each laboratory with the azithromycin and ceftriaxone MIC results consistent to the reference agar dilution method while the cefixime result tended to provide a lower MIC value.

A Novel Acoustomicrofluidic Nebulization Technique Yielding New Crystallization Morphologies.

A novel acoustic microfluidic nebulization platform is demonstrated, which, due to its unique ability to access intermediate evaporation rate regimes-significantly faster than that in slow solvent evaporation but considerably below that achieved in spray drying, is capable of producing novel crystal morphologies that have yet to be reported in both model inorganic and organic systems. In addition, the potential for simultaneously encapsulating single crystals within a biodegradable polymeric coating in a single simultaneous step together with the crystallization process as the solvent evaporates during nebulization is briefly shown. The platform not only has the potential to be highly scalable by employing a large number of these low-cost miniature devices in parallel to achieve industrially relevant particle production rates, but could also be advantageous over conventional spray drying in terms of energy utilization, given the tremendous efficiency associated with the high-frequency ultrasonic microdevice as well as its ambient temperature operation.

Validation of the XDP-MDSP rating scale for the evaluation of patients with X-linked dystonia-parkinsonism.

X-linked dystonia-parkinsonism(XDP) is a neurodegenerative disorder endemic to the Philippines. A rating scale was developed by the authors under the guidance of the Movement Disorder Society of the Philippines (MDSP) to assess XDP severity and progression, functional impact, and response to treatment in future clinical trials. Our main objective was to validate our new scale, the XDP-MDSP scale. The initial validation process included pragmatic testing to XDP patients followed by a modified Delphi procedure with an international advisory panel of dystonia, parkinsonism and scale development experts. Pearson correlation was used to assess construct validity of our new scale versus the assess construct validity of our new scale versus standard dystonia, parkinsonism, non-motor and functional scales; and also to assess divergent validity against behavioral and cognitive scales. The 37-item XDP-MDSP scale has five parts: I-dystonia, II-parkinsonism, III-non-motor features, IV-ADL, and V-global impression. After initial validation, the scale was administered to 204 XDP patients. Inter-domain correlation for the first four parts was acceptable. The correlation between these domains and the global rating was slightly lower. Correlations between Parts I, II, III, and IV versus standard dystonia, parkinsonism, non-motor and functional scales were acceptable with values ranging from 0.323 to 0.428. For divergent validity, a significant correlation was seen with behavioral scales. No significant correlation was noted with the cognitive scale. The proposed XDP-MDSP scale is internally valid but the global rating subscale may need to be modified or eliminated. While there is convergent validity, divergent validation was successful only on cognitive and not behavioral scales. The frequent co-occurrence of anxiety and depression, and its effect on the motor and functional state, may explain this finding.

Dysfunctions in striatal microstructure can enhance perceptual decision making through deficits in predictive coding.

An important brain function is to predict upcoming events on the basis of extracted regularities of previous inputs. These predictive coding processes can disturb performance in concurrent perceptual decision-making and are known to depend on fronto-striatal circuits. However, it is unknown whether, and if so, to what extent striatal microstructural properties modulate these processes. We addressed this question in a human disease model of striosomal dysfunction, i.e. X-linked dystonia-parkinsonism (XDP), using high-density EEG recordings and source localization. The results show faster and more accurate perceptual decision-making performance during distraction in XDP patients compared to healthy controls. The electrophysiological data show that sensory memory and predictive coding processes reflected by the mismatch negativity related to lateral prefrontal brain regions were weakened in XDP patients and thus induced less cognitive conflict than in controls as reflected by the N2 event-related potential (ERP). Consequently, attentional shifting (P3a ERP) and reorientation processes (RON ERP) were less pronounced in the XDP group. Taken together, these results suggests that striosomal dysfunction is related to predictive coding deficits leading to a better performance in concomitant perceptual decision-making, probably because predictive coding does not interfere with perceptual decision-making processes. These effects may reflect striatal imbalances between the striosomes and the matrix compartment.

Sonographic alteration of substantia nigra is related to parkinsonism-predominant course of X-linked dystonia-parkinsonism.

INTRODUCTION: X-linked recessive dystonia-parkinsonism (XDP, DYT3) is highly prevalent in the Philippines and manifests with varying phenotype. We sought to evaluate the significance of transcranial brain sonography as a biomarker for parkinsonism-predominant phenotype. METHODS: 90 Filipino participants were enrolled into a cross-sectional study: 39 patients with XDP, 21 asymptomatic first-degree relatives of XDP patients, and 30 healthy control subjects. Echogenicity of the substantia nigra and the lenticular nuclei was digitally quantified. Brain sonography data were compared with video-based clinical assessment, genetic status and pedigree charts. RESULTS: The majority of patients had hyperechogenicity of the substantia nigra (79%) and/or the lenticular nuclei (81%). Disease duration correlated with echointensity of lenticular nuclei (Pearson test, r = 0.55, p = 0.029) but not substantia nigra (p = 0.31). Abnormal substantia-nigra hyperechogenicity was more frequent in patients with prominent parkinsonism (100%) compared to those without (68%; χ2 test, p = 0.035). The grading of substantia-nigra echogenicity (normal/increased) in patients was in all cases identical to that in their respective asymptomatic relatives. All patients with "familial" substantia-nigra normoechogenicity presented with a phenotype of predominant dystonia and only mild parkinsonism. In turn, "familial" substantia-nigra hyperechogenicity indicated a phenotype with moderate to severe parkinsonism (sensitivity, 100%; specificity, 67%; Fisher test, p = 0.021). CONCLUSION: Findings imply early alteration of the substantia nigra in XDP mutation carriers prone to develop parkinsonism. Thus, substantia-nigra hyperechogenicity may be regarded as a preclinical risk marker of parkinsonism-predominant XDP. Furthermore, this biomarker is clustered in some families suggesting the existence of one or more genetic co-factors influencing the phenotype of the disease.

Striosomal dysfunction affects behavioral adaptation but not impulsivity-Evidence from X-linked dystonia-parkinsonism.

BACKGROUND: Executive functions including behavioral adaptation and impulse control are commonly impaired in movement disorders caused by striatal pathology. However, as yet it is unclear what aspects of behavioral abnormalities are related to pathology in which striatal subcomponent, that is, the matrix and the striosomes. We therefore studied cognitive control in X-linked dystonia-parkinsonism, a model disease of striosomal degeneration, using behavioral paradigms and EEG. METHODS: We studied genetically confirmed X-linked dystonia-parkinsonism patients (N = 21) in their early disease stages and healthy matched controls. Error-related behavioral adaptation was tested in a flanker task and response inhibition in a Go/Nogo paradigm during EEG. We focused on error-related negativity during error processing and the Nogo-N2 and Nogo-P3 in the response inhibition task. Source localization analyses were calculated. In addition, total wavelet power and phase-locking factor reflecting neural synchronization processes in time and frequency across trials were calculated. RESULTS: Error processing and behavioral adaptation predominantly engaging the anterior cingulate cortex was markedly impaired in X-linked dystonia-parkinsonism. This was reflected in abnormal reaction times correlating with error-related negativity amplitudes, error related theta band activity, and the phase-locking factor. Also, abnormal error processing correlated with dystonia severity but not with parkinsonism. Response inhibition and corresponding EEG activity were normal. CONCLUSIONS: This dissociable pattern of cognitive deficits most likely reflects predominant dysfunction of the striosomal compartment and its connections to the anterior cingulate cortex in X-linked dystonia-parkinsonism. The results underscore the importance of striosomes for cognitive function in humans and suggest that striosomes are relays of error-related behavioral adaptation but not inhibitory control. © 2017 International Parkinson and Movement Disorder Society.

Neuroanatomical changes extend beyond striatal atrophy in X-linked dystonia parkinsonism.

BACKGROUND: X-linked dystonia-parkinsonism (XDP) is an inherited neurodegenerative adult-onset basal ganglia model disease associated with severe striatal atrophy. Anatomical changes exceeding striatal pathology were not yet described in XDP. The present study aimed to assess the microstructure of white matter tracts in XDP using magnetic resonance tomography. METHODS: Diffusion-weighted imaging was done in 10 XDP patients, aged 42.2 years (SD 8.1), and 14 ethnicity and age-matched controls, aged 40.2 years (SD 6.4). Based on diffusion tensor images, mean diffusivity (MD) and fractional anisotropy (FA) maps were calculated. RESULTS: Except for in the occipital lobe, XDP patients showed generally increased MD values across the entire white matter. FA map analysis identified four significant clusters with controls showing higher FA values than XDP patients. Involved regions included the fornix, anterior thalamic radiation, corticospinal tract, and superior corona radiata bilaterally. In the fornix and the anterior thalamic radiation, the UPDRSIII total score showed a negative correlation with mean FA values at a trend level (tau = -0.40, p = 0.053). Volumetric analysis revealed significant gray matter volume loss of putamen (F(1,19) = 44.2, p < 0.001), caudate nucleus (F(1,19) = 54.3, p < 0.001), and pallidum (F(1,19) = 8.9, p = 0.007). CONCLUSIONS: The present study confirms striatal atrophy in XDP and provides evidence for a strong involvement of the white matter and the pallidum. This calls into question the previously held concept of exclusive striatal atrophy in this unique movement disorder. The spared occipital region may point towards a lack of anatomical connections with the atrophied striatum.

Evidence of TAF1 dysfunction in peripheral models of X-linked dystonia-parkinsonism.

The molecular dysfunction in X-linked dystonia-parkinsonism is not completely understood. Thus far, only noncoding alterations have been found in genetic analyses, located in or nearby the TATA-box binding protein-associated factor 1 (TAF1) gene. Given that this gene is ubiquitously expressed and is a critical component of the cellular transcription machinery, we sought to study differential gene expression in peripheral models by performing microarray-based expression profiling in blood and fibroblasts, and comparing gene expression in affected individuals vs. ethnically matched controls. Validation was performed via quantitative polymerase chain reaction in discovery and independent replication sets. We observed consistent downregulation of common TAF1 transcripts in samples from affected individuals in gene-level and high-throughput experiments. This signal was accompanied by a downstream effect in the microarray, reflected by the dysregulation of 307 genes in the disease group. Gene Ontology and network analyses revealed enrichment of genes involved in RNA polymerase II-dependent transcription, a pathway relevant to TAF1 function. Thus, the results converge on TAF1 dysfunction in peripheral models of X-linked dystonia-parkinsonism, and provide evidence of altered expression of a canonical gene in this disease. Furthermore, our study illustrates a link between the previously described genetic alterations and TAF1 dysfunction at the transcriptome level.

Healthcare-Associated Transmission of Plasmodium falciparum in New York City.

A patient with no risk factors for malaria was hospitalized in New York City with Plasmodium falciparum infection. After investigating all potential sources of infection, we concluded the patient had been exposed to malaria while hospitalized less than 3 weeks earlier. Molecular genotyping implicated patient-to-patient transmission in a hospital setting. Infect. Control Hosp. Epidemiol. 2015;37(1):113-115.