A HANC Risk Stratification Score for Antiplatelet Therapy Optimization with Low-Dose Prasugrel in Taiwanese Acute Coronary Syndrome Patients from the Switch Study.

Background: A significant proportion of acute coronary syndrome (ACS) patients experience high on-treatment platelet reactivity (HPR) on clopidogrel-based dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI). Objectives: This study assessed key independent risk factors associated with significant HPR risk on clopidogrel, but not prasugrel, in the Switch Study cohort of 200 Taiwanese ACS patients who switched from clopidogrel to low-dose prasugrel for maintenance DAPT after PCI. Methods: Univariate analysis and stepwise multivariate logistic regression analysis were conducted to identify key independent risk factors for HPR on clopidogrel, but not prasugrel. Results: A HANC [H: low hemoglobin (< 13 g/dL for men and < 12 g/dL for women); A: age ≥ 65 years; N: non-ST elevation myocardial infarction; C: chronic kidney disease as defined by estimated glomerular filtration rate < 60 mL/min] risk stratification score was developed, and demonstrated optimal sensitivity and specificity at a cutoff score of ≥ 2. The HANC score compared favorably against the recently validated ABCD score in the full Switch Study cohort (n = 200), and the ABCD-GENE score in a genotyped cohort (n = 102). Conclusions: The HANC score may serve to alert clinicians to patients at potentially higher HPR risk on clopidogrel, but not prasugrel. Further research to validate this score and assess its correlation with clinical outcomes is warranted.

Effect of CYP2C19 status on platelet reactivity in Taiwanese acute coronary syndrome patients switching to prasugrel from clopidogrel: Switch Study.

BACKGROUND/PURPOSE: Pharmacogenetics is a potential driver of the "East Asian paradox," in which East Asian acute coronary syndrome (ACS) patients receiving dual antiplatelet therapy (DAPT) with clopidogrel following percutaneous coronary intervention (PCI) demonstrate higher levels of platelet reactivity on treatment than Western patients, yet have lower ischemic risk and higher bleeding risk at comparable doses. However, the impact of pharmacogenetics, particularly regarding CYP2C19 genotype, on the pharmacodynamics of P2Y12 inhibitors has not been extensively studied in Taiwanese ACS patients as yet. METHODS: CYP2C19 genotyping and pharmacogenetic analysis was conducted on 102 subjects from the Switch Study, a multicenter, single-arm, open-label intervention study that examined the effects on platelet activity and clinical outcomes of switching from clopidogrel (75 mg daily) to low-dose prasugrel (3.75 mg daily) for maintenance DAPT after PCI in 203 Taiwanese ACS patients. RESULTS: Genotyping results revealed that 43.1% were CYP2C19 extensive metabolizers (EM), while 56.9% were reduced metabolizers (RM). After switching to prasugrel, mean P2Y12 reaction units (PRU) values were significantly reduced in both EM and RM populations, while the proportion of high on-treatment platelet reactivity (HPR) patients significantly declined in RM patients. No increase in bleeding risk after switching was observed during follow-up. Multivariate analysis indicated that for RM patients, low estimated glomerular filtration rate (eGFR) and low hemoglobin were associated with greater HPR risk on clopidogrel, but not after switching to prasugrel. CONCLUSION: Switching to low-dose prasugrel from clopidogrel reduced mean PRU levels and proportion of HPR patients, with more significant reduction in RM patients.

Prasugrel switching from clopidogrel after percutaneous coronary intervention for acute coronary syndrome in Taiwanese patients: an analysis of safety and efficacy.

The recommended maintenance dose of prasugrel for East Asian populations (i.e., Japanese and Taiwanese) is 3.75 mg as part of dual antiplatelet therapy (DAPT) for the prevention of recurrent ischemia and stent thrombosis in acute coronary syndrome (ACS). This modified dosage regimen has been established in studies conducted in Japan; however, the efficacy and safety of switching from clopidogrel to prasugrel DAPT among Taiwanese patients remain to be explored. In this phase IV, multicenter, single-arm, open-label study, we evaluated the 4-week pharmacodynamic response, and the 48-week safety outcomes of prasugrel 3.75 mg after a switch from clopidogrel in Taiwanese ACS patients. A total of 203 prasugrel-naïve ACS patients (over 90% male) who had received post-PCI clopidogrel DAPT for at least 2 weeks were enrolled from ten medical centers in Taiwan and subsequently switched to prasugrel 3.75 mg DAPT. Four weeks after the switch, P2Y12 reaction unit (PRU) values were significantly decreased in the total cohort (mean - 18.2 ± 48.1; 95% confidence interval - 24.9 to - 11.5, p < 0.001), and there was an overall consistent antiplatelet response in the treated subjects. The proportion of patients with high on-treatment platelet reactivity (HPR; PRU > 208) dropped from 23.5 to 10% (p < 0.001). Female sex was associated with a greater PRU reduction with prasugrel, whereas HPR at baseline, age ≥ 65 years, and body mass index ≥ 25 best predicted HPR at Week 4. Throughout the 48-week treatment with prasugrel, the incidences of MACE (1.0%) and TIMI major bleeding (2.0%) were rather low, accompanying an acceptable safety profile of TIMI minor (6.4%) and non-major, non-minor clinically relevant bleeding (3.0%). Overall, switching to the maintenance dose of prasugrel (3.75 mg) was observed to be effective and well tolerated among post-PCI ACS patients in Taiwan. Clinical Trial Registration Number: NCT03672097.

Effect of Size-Dependent Photodestructive Efficacy by Gold Nanomaterials with Multiphoton Laser.

The photostability, photodestructive efficacy, two-photon excitation cross section, and two-photon fluorescence of gold nanoparticles conjugated with a hydrophilic photosensitizer, indocyanine green, via multiphoton laser exhibited an increased size effect in methicillin-resistant Staphylococcus aureus and A549 cancer cells that was dependent on the size of multifunctional gold nanomaterials, but the effect only occurred when nanomaterials within 100 nm in diameter were used. Besides, the enhanced effectiveness of photodestruction, photostability, and contrast probe indicated an additive effect in the therapeutic and imaging efficiency of multifunctional gold nanomaterials. Consequently, the preparation of the multifunctional gold nanomaterials and their use in biomedical applications via multiphoton laser is an alternative and potential therapeutic approach for killing bacteria and for ablating cancer cells.

High-throughput multiphoton-induced three-dimensional ablation and imaging for biotissues.

In this study, a temporal focusing-based high-throughput multiphoton-induced ablation system with axially-resolved widefield multiphoton excitation has been successfully applied to rapidly disrupt biotissues. Experimental results demonstrate that this technique features high efficiency for achieving large-area laser ablation without causing serious photothermal damage in non-ablated regions. Furthermore, the rate of tissue processing can reach around 1.6 × 10(6) µm(3)/s in chicken tendon. Moreover, the temporal focusing-based multiphoton system can be efficiently utilized in optical imaging through iterating high-throughput multiphoton-induced ablation machining followed by widefield optical sectioning; hence, it has the potential to obtain molecular images for a whole bio-specimen.

Measurements of multiphoton action cross sections for multiphoton microscopy.

We report quantitative measurements of two-, three-, and four-photon excitation action cross sections of several commonly used fluorophores and fluorescent proteins at three different excitation wavelengths of 800 nm, 1300 nm, and 1680 nm. The measured cross section values are consistent with simple quantum mechanic estimations. These values indicate that the optimum repetition rate for deep tissue 3-photon microscopy is approximately 1 to 2 MHz. We further demonstrate that it is feasible to perform 4-photon fluorescence microscopy of GFP labeled microglia in mouse brain in vivo at 1700 nm. 4-photon excitation increases the accessibility of fluorophores at the long wavelength spectral window of 1700 nm.

Graphene oxide-based micropatterns via high-throughput multiphoton-induced reduction and ablation.

In this study, a developed temporal focusing-based femtosecond laser system provides high-throughput multiphoton-induced reduction and ablation of graphene oxide (GO) films. Integrated with a digital micromirror device to locally control the laser pulse numbers, GO-based micropatterns can be quickly achieved instantly. Furthermore, the degree of reduction and ablation can be precisely adjusted via controlling the laser wavelength, power, and pulse number. Compared to point-by-point scanning laser direct writing, this approach offers a high-throughput and multiple-function approach to accomplish a large area of micro-scale patterns on GO films. The high-throughput micropatterning of GO via the temporal focusing-based femtosecond laser system fulfills the requirement of mass production for GO-based applications in microelectronic devices.

Nonlinear structured-illumination enhanced temporal focusing multiphoton excitation microscopy with a digital micromirror device.

In this study, the light diffraction of temporal focusing multiphoton excitation microscopy (TFMPEM) and the excitation patterning of nonlinear structured-illumination microscopy (NSIM) can be simultaneously and accurately implemented via a single high-resolution digital micromirror device. The lateral and axial spatial resolutions of the TFMPEM are remarkably improved through the second-order NSIM and projected structured light, respectively. The experimental results demonstrate that the lateral and axial resolutions are enhanced from 397 nm to 168 nm (2.4-fold) and from 2.33 µm to 1.22 µm (1.9-fold), respectively, in full width at the half maximum. Furthermore, a three-dimensionally rendered image of a cytoskeleton cell featuring ~25 nm microtubules is improved, with other microtubules at a distance near the lateral resolution of 168 nm also able to be distinguished.

Wavefront sensorless adaptive optics temporal focusing-based multiphoton microscopy.

Temporal profile distortions reduce excitation efficiency and image quality in temporal focusing-based multiphoton microscopy. In order to compensate the distortions, a wavefront sensorless adaptive optics system (AOS) was integrated into the microscope. The feedback control signal of the AOS was acquired from local image intensity maximization via a hill-climbing algorithm. The control signal was then utilized to drive a deformable mirror in such a way as to eliminate the distortions. With the AOS correction, not only is the axial excitation symmetrically refocused, but the axial resolution with full two-photon excited fluorescence (TPEF) intensity is also maintained. Hence, the contrast of the TPEF image of a R6G-doped PMMA thin film is enhanced along with a 3.7-fold increase in intensity. Furthermore, the TPEF image quality of 1µm fluorescent beads sealed in agarose gel at different depths is improved.

Temporal focusing-based multiphoton excitation microscopy via digital micromirror device.

This Letter presents an enhanced temporal focusing-based multiphoton excitation (MPE) microscope in which the conventional diffraction grating is replaced by a digital micromirror device (DMD). Experimental results from imaging a thin fluorescence film show that the 4.0 µm axial resolution of the microscope is comparable with that of a setup incorporating a 600 lines/mm grating; hence, the optical sectioning ability of the proposed setup is demonstrated. Similar to a grating, the DMD diffracts illuminating light frequencies for temporal focusing; additionally, it generates arbitrary patterns. Since the DMD is placed on the image-conjugate plane of the objective lens' focal plane, the MPE pattern can be projected on the focal plane precisely.

High-throughput fabrication of gray-level biomicrostructures via temporal focusing excitation and laser pulse control.

ABSTRACT. A developed temporal focusing-based multiphoton excitation system with additional patterned excitation and local laser control can provide high-throughput fabrication of three-dimensional gray-level biomicrostructures via two-photon cross-linking with rose bengal (RB) as the photoactivator. Multiple bovine serum albumin (BSA) structures of different concentrations were simultaneously achieved by selecting different pulse numbers in the designated regions with an appropriate femtosecond laser power within a few seconds. Intensity of the RB two-photon excited fluorescence (TPEF) is correlated to the concentration of the fabricated cross-linked BSA microstructure. Hence, the fabricated BSA microstructure can be monitored online by utilizing the RB TPEF as contrast agent. It suggests that this approach with its unique capability of high-speed, gray-level, and online-inspection fabrication meets the requirements of the biomedical researches involved in extracellular matrix.

Fast multiphoton microfabrication of freeform polymer microstructures by spatiotemporal focusing and patterned excitation.

One of the limits of conventional scanning multiphoton microfabrication is its low throughput due to point-by-point processing. In order to surpass this limit, a multiphoton microfabrication system based on spatiotemporal focusing and patterned excitation has been developed to quickly provide three-dimensional (3D) freeform polymer microstructures. 3D freeform polymer microstructures using Rose Bengal as the photoinitiator are created by sequentially stacking two-dimensional fabricating patterns. The size of each fabrication area can be larger than 300 × 170 µm2 (full width at half maximum). Compared to conventional scanning multiphoton excitation and fixed mask pattern generation, this approach offers freeform microstructures and a greater than three-order increase in fabrication speed. Furthermore, the system is capable of optically sectioning the fabricated microstructures for providing 3D inspection.

Spatiotemporal focusing-based widefield multiphoton microscopy for fast optical sectioning.

In this study, a microscope based on spatiotemporal focusing offering widefield multiphoton excitation has been developed to provide fast optical sectioning images. Key features of this microscope are the integrations of a 10 kHz repetition rate ultrafast amplifier featuring high instantaneous peak power (maximum 400 µJ/pulse at a 90 fs pulse width) and a TE-cooled, ultra-sensitive photon detecting, electron multiplying charge-coupled camera into a spatiotemporal focusing microscope. This configuration can produce multiphoton images with an excitation area larger than 200 × 100 µm² at a frame rate greater than 100 Hz (current maximum of 200 Hz). Brownian motions of fluorescent microbeads as small as 0.5 µm were observed in real-time with a lateral spatial resolution of less than 0.5 µm and an axial resolution of approximately 3.5 µm. Furthermore, second harmonic images of chicken tendons demonstrate that the developed widefield multiphoton microscope can provide high resolution z-sectioning for bioimaging.