Strengthening premarket and postmarket surveillance of medical devices has long been an area of focus for health policy makers. The recent class I recall (the most serious of the US Food and Drug ...Administration FDA recalls) of reperfusion catheters manufactured by Penumbra, a US-based medical device company, illustrates issues of device safety and oversight that mandate attention.
To review the regulatory history and clinical evidence of the Penumbra JET 7 Reperfusion Catheter with Xtra Flex Technology (JET 7) and use the device recall as a case study of the challenges associated with clinical evaluation, transparency, and oversight of medical devices in the US.
Regulatory history and clinical evidence for the Penumbra medical devices were analyzed through a qualitative review of decision letters in the Access FDA database for medical devices and medical device reports in the Manufacturer and User Facility Device Experience database and a review of market data (eg, earnings calls, company communications) and clinical literature.
The JET 7 device was subjected to a class I recall following more than 200 adverse event reports, 14 of which involved patient deaths. Regulatory analysis indicated that each of the Penumbra reperfusion catheters was cleared under the 510(k) pathway (which allows devices to be authorized with limited to no clinical evidence), with limited submission of either new clinical or animal data. Clinical evidence for Penumbra devices was generated from nonrandomized, single-arm trials with small sample sizes. The regulatory issues raised by JET 7 are reflective of broader challenges for medical device regulation. Opportunities for reform include strengthening premarket evidence requirements, requiring safety reporting with unique device identifiers, and mandating active methods of postmarket surveillance.
The case study of JET 7 highlights the long-standing gaps in medical device oversight and renews the impetus to build on the Institute of Medicine recommendations and reform FDA medical device regulation to protect public health.
Abstract In response to the problems of many influencing factors and different indexes, a radar equipment testability assessment index system is constructed based on the characteristics of equipment ...and testability connotation requirements. The Criteria Importance Though the Intercrieria Correlation (CRITIC) method is improved by using the variance coefficient to replace standard deviation and conflict coefficient to calculate the absolute value, and the objective weights of evaluation indexes are determined. An improved matter-element extension model is established, and the testability evaluation of different types of radar equipment is obtained by calculating the asymmetric close degree of the extension set. The effectiveness of the model is verified by an example analysis.
We introduce a microfluidic refractive index sensor based on a directional coupler architecture using solid-core photonic crystal fibers. The sensor achieves very high sensitivity by coupling the ...core mode to a mode in the adjacent fluid-filled waveguide that is beyond modal cutoff, and with strong field overlap. We demonstrate the device through the selective infiltration of a single hole with fluid along a microstructured optical fiber. A detection limit of 4.6x10(-7) refractive index units has been derived from measurements with a sensitivity of 30,100 nm per refractive index unit, which is the highest for a fiber device to date.
We demonstrate reduced graphene oxide as the active material for high-performance molecular sensors. Sensors are fabricated from exfoliated graphene oxide platelets that are deposited to form an ...ultrathin continuous network. These graphene oxide networks are tunably reduced toward graphene by varying the exposure time to a hydrazine hydrate vapor. The conductance change of the networks upon exposure to trace levels of vapor is measured as a function of the chemical reduction. The level of reduction affects both the sensitivity and the level of 1/f noise. The sensors are capable of detecting 10 s exposures to simulants of the three main classes of chemical-warfare agents and an explosive at parts-per-billion concentrations.
We demonstrate a fiber in-line Fabry-Perot interferometer cavity sensor for refractive index measurement. The interferometer cavity is formed by drilling a micro-hole at the cleaved fiber end facet, ...followed by fusion splicing. A micro-channel is inscribed by femtosecond laser micromachining to vertically cross the cavity to allow liquid to flow in. The refractive index sensitivity obtained is ~994 nm/RIU (refractive index unit). Such a device is simple in configuration, easy for fabrication and reliable in operation due to extremely low temperature cross sensitivity of ~4.8 × 10(-6) RIU/°C.
Chronic infections can lead to carcinogenesis through inflammation-related mechanisms. Chronic infection of the human gastric mucosa with Helicobacter pylori is a well-known risk factor for gastric ...cancer. However, the mechanisms underlying H. pylori-induced gastric carcinogenesis are incompletely defined. We aimed to screen and clarify the functions of long noncoding RNAs (lncRNAs) that are differentially expressed in H. pylori-related gastric cancer. We found that lncRNA SNHG17 was upregulated by H. pylori infection and markedly increased the levels of double-strand breaks (DSBs). SNHG17 overexpression correlated with poor overall survival in patients with gastric cancer. The recruitment of NONO by overabundant nuclear SNHG17, along with the role of cytoplasmic SNHG17 as a decoy for miR-3909, which regulates Rad51 expression, shifted the DSB repair balance from homologous recombination toward nonhomologous end joining. Notably, during chronic H. pylori infection, SNHG17 knockdown inhibited chromosomal aberrations. Our findings suggest that spatially independent deregulation of the SNHG17/NONO and SNHG17/miR-3909/RING1/Rad51 pathways upon H. pylori infection promotes tumorigenesis in gastric cancer by altering the DNA repair system, which is critical for the maintenance of genomic stability. Upregulation of SNHG17 by H. pylori infection might be an undefined link between cancer and inflammation.
Using a photoalignment technique with a sulphonic azo-dye as the surfactant aligning material, we fabricated electrically tunable liquid crystal q-plates with topological charge 0.5, 1.5 and 3 for ...generating optical vortex beams with definite orbital angular momentum (OAM) 1,3 and 6 per photon (in units of ¯h), respectively. We carried out several tests on our q-plates, including OAM tomography, finding excellent performances. These devices can have useful applications in general and quantum optics.
Symmetry-breaking introduced by an adjacent semi-infinite dielectric can introduce coupling and hybridization of the plasmon modes of a metallic nanostructure. This effect is particularly large for ...entities with a large contact area adjacent to the dielectric. For a nanocube, a nearby dielectric mediates an interaction between bright dipolar and dark quadrupolar modes, resulting in bonding and antibonding hybridized modes. The Fano resonance that dominates the scattering spectrum arises from the interference of these modes. This analysis provides a strategy for optimizing the sensitivity of nanostructures, whether chemically synthesized or grown by deposition methods, as high-performance localized surface plasmon resonance sensors.
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