Zebrafish as a Model for Osteoporosis: Functional Validations of Genome-Wide Association Studies

PURPOSE OF REVIEW

GWAS, as a largely correlational analysis, requires in vitro or in vivo validation. Zebrafish (Danio rerio) have many advantages for studying the genetics of human diseases. Since gene editing in zebrafish has been highly valuable for studying embryonic skeletal developmental processes that are prenatally or perinatally lethal in mammalian models, we are reviewing pros and cons of this model.

RECENT FINDINGS

The true power for the use of zebrafish is the ease by which the genome can be edited, especially using the CRISPR/Cas9 system. Gene editing, followed by phenotyping, for complex traits such as BMD, is beneficial, but the major physiological differences between the fish and mammals must be considered. Like mammals, zebrafish do have main bone cells; thus, both in vivo stem cell analyses and in vivo imaging are doable. Yet, the "long" bones of fish are peculiar, and their bone cavities do not contain bone marrow. Partial duplication of the zebrafish genome should be taken into account. Overall, small fish toolkit can provide unmatched opportunities for genetic modifications and morphological investigation as a follow-up to human-first discovery.

The real-world safety profile of SGLT2 inhibitors among adults 75 years or older: a retrospective, pharmacovigilance study

Introduction

As indications for sodium-glucose co-transporter-2 (SGLT2) inhibitors treatment are expanding, more older adults become candidates for treatment. However, data regarding the treatment's safety profile in the older population are limited.

Methods

A retrospective, pharmacovigilance study of the FDA's global database of safety reports (7/1/2014–6/30/2021). To assess reporting of pre-specified adverse events following SGLT2-inhibitors treatment among adults (18≥age<75) and older adults (age≥75), we performed disproportionality analysis using the reporting odds ratio (ROR).

Results

Of 10,526,408 patients in the full database, 279,619 eligible patients with non-insulin-dependent diabetes mellitus were identified (mean age 63.4 [SD 13.0] years, 54,791 [19.6%] aged ≥75 years), among whom 29,431 receiving SGLT-2 inhibitors. Compared to other non-insulin anti-diabetics, SGLT2-inhibitors were significantly associated with amputations (ROR=127.87 [95% CI: 111.31–146.90] vs ROR=74.91 [49.99–112.25]), Fournier gangrene (ROR=53.27 [44.38–63.92] vs ROR=33.33 [20.33–54.64]), diabetes ketoacidosis (ROR=39.25 [37.20–41.42] vs ROR=58.46 [49.41–69.1]), genitourinary infections (ROR=4.36 [4.12–4.61] vs ROR=5.08 [4.45–5.79]), nocturia (ROR=2.81 [2.13–3.73] vs ROR=3.51 [1.84–6.68]), and dehydration (ROR=2.22 [2.05–2.40] vs ROR=2.33 [1.93–2.81]) in both adults and older adults, respectively. The relative reporting of these safety signals was consistent between age groups (all P interaction >0.05). Acute kidney injury was associated with SGLT2-inhibitors treatment in adults (ROR=1.47 [1.40–1.54]) but not older adults (ROR=0.84 [0.72–0.98]). No new safety signals were observed in older adults. Falls, fractures, hypotension, and syncope were not associated with SGLT2-inhibitors among either adults or older adults.

Conclusion

In this global post-marketing study, treatment with SGLT-2 inhibitors in older adults was associated with increased reporting of amputations, Fournier gangrene, DKA, genitourinary infections, and dehydration. Nevertheless, the relative reporting was consistent between adults and older adults, and no new safety signals were found in the older population.

Funding Acknowledgement

Type of funding sources: None.

Long lifetime of bialkali photocathodes operating in high gradient superconducting radio frequency gun

High brightness, high charge electron beams are critical for a number of advanced accelerator applications. The initial emittance of the electron beam, which is determined by the mean transverse energy (MTE) and laser spot size, is one of the most important parameters determining the beam quality. The bialkali photocathodes illuminated by a visible laser have the advantages of high quantum efficiency (QE) and low MTE. Furthermore, Superconducting Radio Frequency (SRF) guns can operate in the continuous wave (CW) mode at high accelerating gradients, e.g. with significant reduction of the laser spot size at the photocathode. Combining the bialkali photocathode with the SRF gun enables generation of high charge, high brightness, and possibly high average current electron beams. However, integrating the high QE semiconductor photocathode into the SRF guns has been challenging. In this article, we report on the development of bialkali photocathodes for successful operation in the SRF gun with months-long lifetime while delivering CW beams with nano-coulomb charge per bunch. This achievement opens a new era for high charge, high brightness CW electron beams.

High-Brightness Continuous-Wave Electron Beams from Superconducting Radio-Frequency Photoemission Gun

Continuous-wave photoinjectors operating at high accelerating gradients promise to revolutionize many areas of science and applications. They can establish the basis for a new generation of monochromatic x-ray free electron lasers, high-brightness hadron beams, or a new generation of microchip production. In this Letter we report on the record-performing superconducting rf electron gun with CsK_{2}Sb photocathode. The gun is generating high charge electron bunches (up to 10  nC/bunch) and low transverse emittances, while operating for months with a single photocathode. This achievement opens a new era in generating high-power beams with a very high average brightness.

Differential microRNAs expression in calcified versus rheumatic aortic valve disease

BACKGROUND

The aortic valve (AV) is the most commonly affected valve in valvular heart diseases (VHDs). The objective of the study is to identify microRNA (miRNA) molecules expressed in VHDs and the differential expression patterns of miRNA in AVs with either calcification or rheumatism etiologies.

METHODS

Human AVs were collected during valve replacement surgery. RNA was extracted and miRNA containing libraries were prepared and sequenced using the next generation sequencing (NGS) approach. miRNAs identified as differentially expressed between the two etiologies were validated by quantitative real-time polymerase chain reaction (qPCR). The receiver operating characteristic (ROC) curve analysis was performed to examine the ability of relevant miRNA to differentiate between calcification and rheumatism etiologies.

RESULTS

Rheumatic and calcified AV samples were prepared for the NGS and were successfully sequenced. The expression was validated by the qPCR approach in 46 AVs, 13 rheumatic, and 33 calcified AVs, confirming that miR-145-5p, miR-199a-5p, and miR-5701 were significantly higher in rheumatic AVs as compared with calcified AVs. ROC curve analysis revealed that miR-145-5p had a sensitivity of 76.92% and a specificity of 94.12%, area under the curve (AUC) = 0.88 (P = .0001), and miR-5701 had a sensitivity of 84.62% and a specificity of 76.47%, AUC = 0.78 (P = .0001), whereas miR-199a-5p had a sensitivity of 84.62%, and a specificity of 57.58%, AUC = 0.73 (P = .0083).

CONCLUSION

We documented differential miRNA expression between AV disease etiologies. The miRNAs identified in this study advance our understanding of the mechanisms underlining AV disease.

Experimental Demonstration of Hadron Beam Cooling Using Radio-Frequency Accelerated Electron Bunches

Cooling of beams of gold ions using electron bunches accelerated with radio-frequency systems was recently experimentally demonstrated in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Such an approach is new and opens the possibility of using this technique at higher energies than possible with electrostatic acceleration of electron beams. The challenges of this approach include generation of electron beams suitable for cooling, delivery of electron bunches of the required quality to the cooling sections without degradation of beam angular divergence and energy spread, achieving the required small angles between electron and ion trajectories in the cooling sections, precise velocity matching between the two beams, high-current operation of the electron accelerator, as well as several physics effects related to bunched-beam cooling. Here we report on the first demonstration of cooling hadron beams using this new approach.

Multi-atmosphere picosecond CO2 amplifier optically pumped at 4.3 μm

The possibility of the amplification of picosecond 10 μm pulses to gigawatt powers in an optically pumped 20 atmosphere CO₂ laser is shown using numerical simulations. Multi-millijoule 4.3 μm pulses generated by a tunable Fe:ZnSe laser are considered for pumping.

Patient-derived xenografts effectively capture responses to oncology therapy in a heterogeneous cohort of patients with solid tumors

Background

While patient-derived xenografts (PDXs) offer a powerful modality for translational cancer research, a precise evaluation of how accurately patient responses correlate with matching PDXs in a large, heterogeneous population is needed for assessing the utility of this platform for preclinical drug-testing and personalized patient cancer treatment.

Patients and methods

Tumors obtained from surgical or biopsy procedures from 237 cancer patients with a variety of solid tumors were implanted into immunodeficient mice and whole-exome sequencing was carried out. For 92 patients, responses to anticancer therapies were compared with that of their corresponding PDX models.

Results

We compared whole-exome sequencing of 237 PDX models with equivalent information in The Cancer Genome Atlas database, demonstrating that tumorgrafts faithfully conserve genetic patterns of the primary tumors. We next screened PDXs established for 92 patients with various solid cancers against the same 129 treatments that were administered clinically and correlated patient outcomes with the responses in corresponding models. Our analysis demonstrates that PDXs accurately replicate patients' clinical outcomes, even as patients undergo several additional cycles of therapy over time, indicating the capacity of these models to correctly guide an oncologist to treatments that are most likely to be of clinical benefit.

Conclusions

Integration of PDX models as a preclinical platform for assessment of drug efficacy may allow a higher success-rate in critical end points of clinical benefit.

Design of a high-bunch-charge 112-MHz superconducting RF photoemission electron source

High-bunch-charge photoemission electron-sources operating in a continuous wave (CW) mode are required for many advanced applications of particle accelerators, such as electron coolers for hadron beams, electron-ion colliders, and free-electron lasers. Superconducting RF (SRF) has several advantages over other electron-gun technologies in CW mode as it offers higher acceleration rate and potentially can generate higher bunch charges and average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory to produce high-brightness and high-bunch-charge bunches for the coherent electron cooling proof-of-principle experiment. The gun utilizes a quarter-wave resonator geometry for assuring beam dynamics and uses high quantum efficiency multi-alkali photocathodes for generating electrons.

Association between specimen length and diagnostic yield of temporal artery biopsy

OBJECTIVES

Temporal artery biopsy (TAB) is performed in patients suspected of giant cell arteritis (GCA). Inadequate TAB specimen length is considered a possible explanation for a negative biopsy in patients with GCA. We investigated the association between specimen length and diagnostic yield of TAB.

METHOD

We conducted a retrospective analysis of 240 patients who underwent TAB in a single hospital between 2000 and 2015. Patients were diagnosed with GCA based on positive TAB or, when TAB was negative, on clinical grounds that fulfilled the American College of Rheumatology (ACR) 1990 criteria. Baseline clinical and laboratory features and TAB length were obtained from medical records. Among patients diagnosed with GCA, the rate of TAB positivity was calculated according to biopsy length (< 5, 5-9, 10-14, and ≥ 20 mm).

RESULTS

Out of 240 patients, 88 were diagnosed with GCA: 62 had a positive TAB and 26 were diagnosed based on clinical grounds despite a negative TAB. Among those who were diagnosed with GCA, the length of the TAB specimen was similar in those with a positive and a negative TAB (1.13 ± 1.68 mm vs. 1.15 ± 0.61 mm, respectively, p = 0.928). The TAB positivity rate was similar among all ranges of biopsy length [< 5 mm: 7/10 (70%); 5-9 mm: 22/31 (71%); 10-14 mm: 11/16 (69%); 15-19 mm: 11/16 (69%); ≥ 20 mm: 11/15 (73%, p = ns] and was similar to the overall biopsy positivity rate.

CONCLUSIONS

Specimen length is not associated with diagnostic yield of TAB.

Is temporal artery biopsy essential in all cases of suspected giant cell arteritis?

OBJECTIVES

Temporal artery biopsy (TAB) is performed in cases of suspected giant cell arteritis (GCA), and is the gold-standard for diagnosis of the disease. Current American College of Rheumatology (ACR) classification criteria may aid in the diagnosis of GCA. We aimed to assess whether TAB is essential in all cases of suspected GCA, or whether ACR criteria can replace the need for this procedure in some cases.

METHODS

Retrospective analysis of 216 patients who underwent TAB in a single hospital between 2000 and 2013. Pre-TAB and post-TAB ACR criteria were calculated. Sensitivity and specificity of ACR criteria for the diagnosis of GCA were assessed.

RESULTS

Overall, 55 patients had histological evidence of GCA.Out of 161 patients with negative TAB findings, 34 were diagnosed with GCA, and 127 were not diagnosed with GCA. Sensitivity of TAB for the diagnosis of GCA was 61.7%. Sensitivity and specificity of ACR criteria for diagnosis of GCA before performing TAB were 68.5% and 58%, respectively. Sensitivity and specificity of ACR criteria after performing TAB biopsy were 89.8% and 64.5%, respectively.

CONCLUSIONS

Temporal artery biopsy should be performed in the majority of patients with suspected GCA, and may be obviated only in patients with a pre-TAB ACR score of ≤ 1. In all other cases, when GCA is suspected, ACR criteria should not be a substitute to TAB, as they are not highly specific.

The external Q factor of a dual-feed coupling for superconducting radio frequency cavities: theoretical and experimental studies

We propose a theoretical model based on network analysis to study the external quality factor (Q factor) of dual-feed coupling for superconducting radio-frequency (SRF) cavities. Specifically, we apply our model to the dual-feed 704 MHz half-cell SRF gun for Brookhaven National Laboratory's prototype Energy Recovery Linac (ERL). The calculations show that the external Q factor of this dual-feed system is adjustable from 10(4) to 10(9) provided that the adjustment range of a phase shifter covers 0°-360°. With a period of 360°, the external Q factor of the coupling system changes periodically with the phase difference between the two coupling arms. When the RF phase of both coupling arms is adjusted simultaneously in the same direction, the external Q factor of the system also changes periodically, but with a period of 180°.

'Silent' carriage of two familial Mediterranean fever gene mutations in large families with only a single identified patient

The presence of two mutations in the familial Mediterranean fever gene, without overt familial Mediterranean fever (FMF), designated as phenotype III, predisposes to developing 'silent' AA amyloidosis, recognized as phenotype II, due to the absence of medical supervision and colchicine prophylaxis. We sought to determine the prevalence of phenotype III in large families with only one subject affected with FMF, in order to assess the population at risk for transformation to phenotype II. A total of seven large families were recruited for the study. Siblings were screened for MEFV mutations and underwent a clinical interview to assess for unrecognized FMF manifestations. Phenotype III, most commonly associated with a V726A/E148Q genotype, was detected in 10% of siblings of index cases from informative families, corresponding to a 10-fold increase in comparison to the expected rate in the general population (p < 0.01). Unnoticed 'FMF-like' manifestations were detected among two siblings in the five families in which the index case was heterozygous, but in none of the siblings of the homozygous index cases. The enrichment for phenotype III and detection of occult FMF in large families, in which only a single member is afflicted with FMF, mandates routine clinical evaluation and genetic screening of siblings.

Inverse free electron lasers and laser wakefield acceleration driven by CO2 lasers

The staged electron laser acceleration (STELLA) experiment demonstrated staging between two laser-driven devices, high trapping efficiency of microbunches within the accelerating field and narrow energy spread during laser acceleration. These are important for practical laser-driven accelerators. STELLA used inverse free electron lasers, which were chosen primarily for convenience. Nevertheless, the STELLA approach can be applied to other laser acceleration methods, in particular, laser-driven plasma accelerators. STELLA is now conducting experiments on laser wakefield acceleration (LWFA). Two novel LWFA approaches are being investigated. In the first one, called pseudo-resonant LWFA, a laser pulse enters a low-density plasma where nonlinear laser/plasma interactions cause the laser pulse shape to steepen, thereby creating strong wakefields. A witness e-beam pulse probes the wakefields. The second one, called seeded self-modulated LWFA, involves sending a seed e-beam pulse into the plasma to initiate wakefield formation. These wakefields are amplified by a laser pulse following shortly after the seed pulse. A second e-beam pulse (witness) follows the seed pulse to probe the wakefields. These LWFA experiments will also be the first ones driven by a CO(2) laser beam.

Observation of anomalously large spectral bandwidth in a high-gain self-amplified spontaneous emission free-electron laser

Observation of ultrawide bandwidth, up to 15% full-width, high-gain operation of a self-amplified spontaneous emission free-election laser (SASE FEL) is reported. This type of lasing is obtained with a strongly chirped beam (deltaE/E approximately 1.7%) emitted from the accelerator. Because of nonlinear pulse compression during transport, a short, high current bunch with strong mismatch errors is injected into the undulator, giving high FEL gain. Start-to-end simulations reproduce key features of the measurements and provide insight into mechanisms, such as angular spread in emitted photon and electron trajectory distributions, which yield novel features in the radiation spectrum.

Demonstration of high-trapping efficiency and narrow energy spread in a laser-driven accelerator

Laser-driven electron accelerators (laser linacs) offer the potential for enabling much more economical and compact devices. However, the development of practical and efficient laser linacs requires accelerating a large ensemble of electrons together ("trapping") while keeping their energy spread small. This has never been realized before for any laser acceleration system. We present here the first demonstration of high-trapping efficiency and narrow energy spread via laser acceleration. Trapping efficiencies of up to 80% and energy spreads down to 0.36% (1 sigma) were demonstrated.

Cohesive acceleration and focusing of relativistic electrons in overdense plasma

We describe our studies of the generation of plasma wake fields by a relativistic electron bunch and of phasing between the longitudinal and transverse fields in the wake. The leading edge of the electron bunch excites a high-amplitude plasma wake inside the overdense plasma column, and the acceleration and focusing wake fields are probed by the bunch tail. By monitoring the dependence of the acceleration upon the plasma's density, we approached the beam-matching condition and achieved an energy gain of 0.6 MeV over the 17 mm plasma length, corresponding to an average acceleration gradient of 35 MeV/m. Wake-induced modulation in energy and angular divergence of the electron bunch are mapped within a wide range of plasma density. We confirm a theoretical prediction about the phase offset between the accelerating and focusing components of plasma wake.

Properties of the ultrashort gain length, self-amplified spontaneous emission free-electron laser in the linear regime and saturation

VISA (Visible to Infrared SASE Amplifier) is a high-gain self-amplified spontaneous emission (SASE) free-electron laser (FEL), which achieved saturation at 840 nm within a single-pass 4-m undulator. The experiment was performed at the Accelerator Test Facility at BNL, using a high brightness 70-MeV electron beam. A gain length shorter than 18 cm has been obtained, yielding a total gain of 2 x 10(8) at saturation. The FEL performance, including the spectral, angular, and statistical properties of SASE radiation, has been characterized for different electron beam conditions. Results are compared to the three-dimensional SASE FEL theory and start-to-end numerical simulations of the entire injector, transport, and FEL systems. An agreement between simulations and experimental results has been obtained at an unprecedented level of detail.

Surface-roughness wakefield measurements at brookhaven accelerator test facility

An experiment has been carried out at the Brookhaven Accelerator Test Facility to investigate the effect of a surface-roughness wakefield in narrow beam tubes with artificially created bumps. The measurements show that the synchronous modes decay significantly due to the randomization of the roughness pattern. It is pointed out that this decay mechanism has not been investigated in the previous experiment at DESY and the investigators' conclusion does not apply for surface-roughness wakefields in real surfaces.

Fundamental and harmonic microbunching in a high-gain self-amplified spontaneous-emission free-electron laser

Electron beam microbunching in both the fundamental and second harmonic in a high-gain self-amplified spontaneous emission free-electron laser (SASE FEL) was experimentally characterized using coherent transition radiation. The microbunching factors for both modes (b(1) and b(2)) approach unity, an indication of FEL saturation. These measurements are compared to the predictions of FEL simulations. The simultaneous capture of the microbunching and SASE radiation for individual micropulses correlate the longitudinal electron beam structure with the FEL gain.

Experimental characterization of nonlinear harmonic radiation from a visible self-amplified spontaneous emission free-electron laser at saturation

Nonlinear harmonic radiation was observed using the VISA self-amplified, spontaneous emission (SASE) free-electron laser (FEL) at saturation. The gain lengths, spectra, and energies of the three lowest SASE FEL modes were experimentally characterized. The measured nonlinear harmonic gain lengths and center spectral wavelengths decrease with harmonic number, n, which is consistent with nonlinear harmonic theory. Both the second and third nonlinear harmonics energies are about 1% of the fundamental energy. These experimental results demonstrate for the first time the feasibility of using nonlinear harmonic SASE FEL radiation to produce coherent, femtosecond x rays.

Characterization of a high-gain harmonic-generation free-electron laser at saturation

We report on an experimental investigation characterizing the output of a high-gain harmonic-generation (HGHG) free-electron laser (FEL) at saturation. A seed CO2 laser at a wavelength of 10.6 microm was used to generate amplified FEL output at 5.3 microm. Measurement of the frequency spectrum, pulse duration, and correlation length of the 5.3 microm output verified that the light is longitudinally coherent. Investigation of the electron energy distribution and output harmonic energies provides evidence for saturated HGHG FEL operation.

First staging of two laser accelerators

Staging of two laser-driven, relativistic electron accelerators has been demonstrated for the first time in a proof-of-principle experiment, whereby two distinct and serial laser accelerators acted on an electron beam in a coherently cumulative manner. Output from a CO2 laser was split into two beams to drive two inverse free electron lasers (IFEL) separated by 2.3 m. The first IFEL served to bunch the electrons into approximately 3 fs microbunches, which were rephased with the laser wave in the second IFEL. This represents a crucial step towards the development of practical laser-driven electron accelerators.

High-gain harmonic-generation free-electron laser

A high-gain harmonic-generation free-electron laser is demonstrated. Our approach uses a laser-seeded free-electron laser to produce amplified, longitudinally coherent, Fourier transform-limited output at a harmonic of the seed laser. A seed carbon dioxide laser at a wavelength of 10.6 micrometers produced saturated, amplified free-electron laser output at the second-harmonic wavelength, 5.3 micrometers. The experiment verifies the theoretical foundation for the technique and prepares the way for the application of this technique in the vacuum ultraviolet region of the spectrum, with the ultimate goal of extending the approach to provide an intense, highly coherent source of hard x-rays.