Nanoporous Gold Biointerfaces: Modifying Nanostructure to Control Neural Cell Coverage and Enhance Electrophysiological Recording Performance.

Nanostructured neural interface coatings have significantly enhanced recording fidelity in both implantable and in vitro devices. As such, nano-porous gold (np-Au) has shown promise as a multifunctional neural interface coating due, in part, to its ability to promote nanostructure-mediated reduction in astrocytic surface coverage while not affecting neuronal coverage. The goal of this study is to provide insight into the mechanisms by which the np-Au nanostructure drives the differential response of neurons versus astrocytes in an in vitro model. Utilizing microfabricated libraries that display varying feature sizes of np-Au, it is demonstrated that np-Au influ-ences neural cell coverage through modulating focal adhesion formation in a feature size-dependent manner. The results here show that surfaces with small (≈30 nm) features control astrocyte spreading through inhibition of focal adhesion formation, while surfaces with large (≈170 nm and greater) features control astrocyte spreading through other mechanotransduction mechanisms. This cellular response combined with lower electrical impedance of np-Au electrodes significantly enhances the fidelity and stability of electrophysiological recordings from cortical neuronglia co-cultures relative to smooth gold electrodes. Finally, by leveraging the effect of nanostructure on neuronal versus glial cell attachment, the use of laser-based nanostructure modulation is demonstrated for selectively patterning neurons with micrometer spatial resolution.

Prostaglandin Availability and Association with Outcomes for Infants with Congenital Heart Disease.

Data regarding availability of prostaglandin E1 (PGE) and its impact on the stabilization, transport, critical care course, and surgical outcome of infants with ductal-dependent congenital heart disease in the current pediatric healthcare environment are unknown. We sought to determine the proportion of hospitals in Texas that stock PGE and to investigate associations between PGE availability and clinical outcomes. All birth institutions listed with the Texas Department of Health and Human Services were contacted to determine PGE availability as of 2011. Outcomes of all infants admitted to our institution from 2007 to 2012 who received PGE for ductal-dependent lesions were evaluated. PGE was stocked in 50 % (n = 139) of hospitals that performed deliveries in Texas in 2011 representing 79.1 % (303, 481) of births. Hospitals that did not stock PGE had less annual births and were located a further distance from a center that provided pediatric cardiac surgical services. Patients born at a hospital that did not stock PGE had significantly greater serum lactate and creatinine (p = 0.002) and serum lactate on admission (p < 0.001). The PGE availability was not associated with hospital length of stay, postoperative length of stay, or mortality. When stratifying in TGA and HLHS subgroups, lack of PGE availability remained associated with higher creatinine, higher lactate, lower glucose, and lower pH. PGE is not universally available in all healthcare institutions providing obstetrical services. Lack of availability of PGE at an outlying hospital was associated with increased morbidity, but was not associated with mortality or length of stay.

An electrically-controlled programmable microfluidic concentration waveform generator.

BACKGROUND: Biological systems have complicated environmental conditions that vary both spatially and temporally. It becomes necessary to impose time-varying soluble factor concentrations to study such systems, including cellular responses to pharmaceuticals, inflammation with waxing and waning cytokine concentrations, as well as circadian rhythms and their metabolic manifestations. There is therefore a need for platforms that can achieve time-varying concentrations with arbitrary waveforms. RESULTS: To address this need, we developed a microfluidic system that can deliver concentration waveforms in a fast and accurate manner by adopting concepts and tools from electrical engineering and fluid mechanics. Specifically, we employed pulse width modulation (PWM), a commonly used method for generating analog signals from digital sources. We implement this technique using three microfluidic components via laser ablation prototyping: low-pass filter (lower frequency signals permitted, high frequency signals blocked), resistor, and mixer. Each microfluidic component was individually studied and iteratively tuned to generate desired concentration waveforms with high accuracy. Using fluorescein as a small-molecule soluble factor surrogate, we demonstrated a series of concentration waveforms, including square, sawtooth, sinusoidal, and triangle waves with frequencies ranging from 100 mHz to 400 mHz. CONCLUSION: We reported the fabrication and characterization of microfluidic platform that can generate time-varying concentrations of fluorescein with arbitrary waveforms. We envision that this platform will enable a wide range of biological studies, where time-varying soluble factor concentrations play a critical role. In addition, the technology is expected to assist in the development of biomedical devices that allow precise dosing of pharmaceuticals for enhanced therapeutic efficacy and reduced toxicity.

Large neurofibroma of the labia majora: A case report.

Neurofibromatosis is an autosomal dominant progressive disorder with an incidence of approximately 1 in 3000 live births. Its recognized features include hyper-pigmented skin lesions (cafe-au-lait spots), neurofibromas, iris hamartomas, macrocephaly, central nervous system tumours, defects of the skull and facial bones, and vascular lesions. Involvement of the external genitalia is extremely unusual. This report describes a case of a vulva neurofibroma in a 15-years old teenage girl with no history of trauma or features of Von Recklinghausen's disease. Treatment involved total excision of the tumour under spinal anaesthesia. The diagnosis of neurofibroma was confirmed by histological examination which showed spindle shaped cells with wavy nuclei arranged in a loose myxomatous stroma. No further treatment was offered but the patient was counselled on the possibility of recurrence. She was seen one month after excision and there were no signs of recurrence.