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May 10 Metals Commentary: Larry Shover

Larry Shover, Efficient Advisors




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May 13 Metals Commentary: Todd Colvin

Todd Colvin, Ambrosino Brothers




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Bacterial protein discovered, engineered to better separate rare earth metals

A newly discovered protein naturally houses an unusual binding site that can differentiate between rare earth elements, and researchers at Penn State have made it even better. Rare earth elements are key components used in everything from modern tech to gasoline production. The protein, called LanD, enriches neodymium and praseodymium over other similar rare earth elements and has the potential to revolutionize industrial mining, researchers said.




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News24 Business | Kenya court rules Meta can be sued over layoffs by contractor

A Kenyan court ruled on Friday that Facebook's parent company Meta could be sued in the East African nation over the dismissal of dozens of content moderators by a contractor.




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OnePlus Ace 5 Series Tipped to Get Metal Middle Frame, Ceramic Body, 24GB RAM, More

OnePlus seems to be preparing to launch the OnePlus Ace 5 and Ace 5 Pro in China. The Chinese tech brand is yet to make an official announcement, but rumours about the duo continue to surface on the Web. As per a new leak, the OnePlus Ace 5 will run on the Snapdragon 8 Gen 3 chipset. The upcoming Ace 5 smartphones are also said to feature a metal middle frame.




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Investor Protection Unit Joins CFTC to Stop Nationwide Precious Metals IRA, Bullion Coin Scheme

Attorney General Jennings announced Tuesday that the Delaware Department of Justice’s Investor Protection Unit is participating in a consolidated nationwide enforcement action to disrupt a fraudulent precious metals scheme that has solicited more than $180 million from seniors and other investors. The Delaware Department of Justice, the U.S. Commodity Futures Trading Commission, and 29 other […]



  • Department of Justice
  • Department of Justice Press Releases
  • News

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Attention Investors – Metals.com, Tower Equity, Chase Metals, and Barrick Capital Receivership Claim Deadline

The Investor Protection Unit of the Delaware Department of Justice is encouraging anyone who invested with precious metals dealers Metals.com, Tower Equity, Chase Metals, or Barrick Capital to learn more about whether they may have been defrauded and the process for potentially recovering some of their losses. In September, the Investor Protection Unit joined the […]



  • Department of Justice
  • Department of Justice Press Releases
  • News

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AG Jennings sues Meta

Attorney General Kathy Jennings announced Tuesday that Delaware has joined a bipartisan coalition of attorneys general suing Meta in federal and state courts, alleging that the company knowingly designed and deployed harmful features that purposefully addict children and teens on Instagram and its other social media platforms. At the same time, Meta falsely assured the […]



  • Department of Justice Press Releases

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4103 Inherited Metabolic Disorders

DEPARTMENT OF HEALTH AND SOCIAL SERVICES: Division of Public Health




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Programming Prodigy To Meta CEO: Inside The Life Of Mark Zuckerberg

Think of social media, and the first name that almost immediately comes to mind is Mark Zuckerberg.




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Change rout design metal layer effort

Hi,

Is there any way to instruct the tool to reduce the low metals effort and route more on top layers? 




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Constraining some nets to route through a specific metal layer, and changing some pin/cell placements and wire directions in Cadence Innovus.

Hello All:

I am looking for help on the following, as I am new to Cadence tools [I have to use Cadence Innovus for Physical Design after Logic Synthesis using Synopsys Design Compiler, using Nangate 45 nm Open Cell Library]: while using Cadence Innovus, I would need to select a few specific nets to be routed through a specific metal layer. How can I do this on Innovus [are there any command(s)]? Also, would writing and sourcing a .tcl script [containing the command(s)] on the Innovus terminal after the Placement Stage of Physical Design be fine for this?

Secondly, is there a way in Innovus to manipulate layout components, such as changing some pin placements, wire directions (say for example, wire direction changed to facing east from west, etc.) or moving specific closely placed cells around (without violating timing constraints of course) using any command(s)/.tcl script? If so, would pin placement changes and constraining some closely placed cells to be moved apart be done after Floorplanning/Powerplanning (that is, prior to Placement) and the wire direction changes be done after Routing? 

While making the necessary changes, could I use the usual Innovus commands to perform Physical Design of the remaining nets/wires/pins/cells, etc., or would anything need modification for the remaining components as well?

I would finally need to dump the entire design containing all of this in a .def file.

I tried looking up but could only find matter on Virtuoso and SKILL scripting, but I'd be using Innovus GUI/terminal with Nangate 45 nm Open Cell Library. I know this is a lot, but I would greatly appreciate your help. Thanks in advance.

Riya




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QSPI Direct Access bare metal SW driver

Hello,

I'm reading the Design specification for IP6514E.

We will use the DAC mode.

It would seem to be very simple but I don't see any code sequence, i.e.

  1.Write 03(Basic Read) to this register

  2, Write start adress to this register

  3. Write "execute" to this register

  4. Read the data from this register

Thanks,

Stefan




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How can I place stacked vias with the size exact same cut width without metals around?

How can I place stacked vias with the size exact same cut width without metals around?
As the red part only in the image below?




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Meta cuts EU ad-free subscription price by 40% for Facebook and Instagram

Meta slashes EU ad-free subscription prices for Facebook and Instagram by 40 percent and adds a less personalized ad-tier option.




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EWC International Media Conference to Feature Nobel Laureate Maria Ressa, Meta Security Policy Chief Nathaniel Gleicher, Other Top Speakers

EWC International Media Conference to Feature Nobel Laureate Maria Ressa, Meta Security Policy Chief Nathaniel Gleicher, Other Top Speakers EWC International Media Conference to Feature Nobel Laureate Maria Ressa, Meta Security Policy Chief Nathaniel Gleicher, Other Top Speakers
ferrard

News Release

Explore

News Release

Explore




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The Next Event on God’s Prophetic Timetable (1 Thessalonians 4:13-18)

Check here each week to keep up with the latest from John MacArthur's pulpit at Grace Community Church.




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The Next Event on God’s Prophetic Timetable, Part 2 (1 Thessalonians 4:13-18)

Check here each week to keep up with the latest from John MacArthur's pulpit at Grace Community Church.




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Keeping the Divine Timetable




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The July Revolution in Bangladesh Is Rooted in Meta-Modernist Philosophy

The students and the common people of Bangladesh dared to do something in 36 days of July-August that was considered simply impossible by most people just days before August 5, 2024. They said ‘enough is enough’ to an old order that outraged their humanity, robbed their dignity and the rulers imagined that their citadel of […]




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Asian Impact Webinar 80: Statistical Data and Metadata eXchange for Enhanced Data Management

Decision makers need to analyze, exchange, and disseminate statistical information effectively in today’s data-driven world. See how Statistical Data and Metadata eXchange (SDMX) standards are helping create robust data links across the globe.




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Vampire bats run on a treadmill to reveal their strange metabolism

Experiments where vampire bats were made to run on a treadmill have revealed how they extract energy from protein in their latest blood meal




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Dead spacecraft are seeding the upper atmosphere with metal

The stratosphere seems to be full of aluminium particles and other metals that come from spacecraft burning up in the atmosphere, and those particles could mess up polar clouds




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Vampire bats run on a treadmill to reveal their strange metabolism

Experiments where vampire bats were made to run on a treadmill have revealed how they extract energy from protein in their latest blood meal




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What Happens to Metabolism in Fasting?

Title: What Happens to Metabolism in Fasting?
Category: Health and Living
Created: 8/26/2022 12:00:00 AM
Last Editorial Review: 8/26/2022 12:00:00 AM




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Even at Low Levels, Toxic Metals Put Heart at Serious Risk: Study

Title: Even at Low Levels, Toxic Metals Put Heart at Serious Risk: Study
Category: Health News
Created: 8/30/2018 12:00:00 AM
Last Editorial Review: 8/30/2018 12:00:00 AM




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Impaired lung function and associated risk factors in children born prematurely: a systematic review and meta-analysis

Background

Immature lung development and respiratory morbidity place preterm-born children at high risk of long-term pulmonary sequelae. This systematic review and meta-analysis aims to quantify lung function in preterm-born children and identify risk factors for a compromised lung function.

Methods

We searched MEDLINE, Embase, Cochrane Library, Web of Science and Scopus for relevant studies published on preterm cohorts born since 1990. Studies comparing forced expiratory volume in 1 s (FEV1) in preterm-born children aged ≥5 years to term-born controls or normative data were included. Study quality was assessed using the Newcastle–Ottawa Scale for cohort studies. Standardised mean differences in FEV1 and secondary spirometry outcomes per study were pooled using meta-analysis. The impact of different demographic and neonatal variables on studies’ FEV1 effect sizes was investigated by meta-regression analyses. Certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations framework.

Results

We identified 42 studies with unique cohorts including 4743 preterm children and 9843 controls. Median gestational age in the studies was 28.0 weeks and age at assessment ranged from 6.7 to 16.7 years. Preterm children had lower FEV1 than controls (–0.58 sd, 95% CI –0.69– –0.47 sd, p<0.001) resulting in a relative risk of 2.9 (95% CI 2.4–3.4) for abnormal outcome, with high certainty of evidence. FEV1 was significantly associated with gestational age, birthweight, bronchopulmonary dysplasia and invasive mechanical ventilation in univariate meta-regression analyses (R2=36–96%).

Conclusion

This systematic review shows robust evidence of impaired lung function in preterm-born children with a high certainty of evidence.




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Epidemiology of severe asthma in children: a systematic review and meta-analysis

Background

Severe asthma significantly impacts a minority of children with asthma, leading to frequent symptoms, hospitalisations and potential long-term health consequences. However, accurate global data on severe asthma epidemiology is lacking. This study aims to address this gap, providing data on severe asthma epidemiology, regional differences and associated comorbidities.

Methods

We conducted a rigorous systematic review and meta-analysis following a registered protocol (PROSPERO CRD42023472845). We searched PubMed, Scopus and Web of Science for cohort or cross-sectional studies published since 2003, evaluating severe asthma incidence and prevalence in children. Study quality and risk of bias were assessed using STROBE guidelines.

Results

Nine studies investigating European children with asthma (aged 5–18 years) were included in the meta-analysis. No significant publication bias was found. The overall severe asthma prevalence in children with asthma was 3% (95% CI 1–6; I2=99.9%; p<0.001), with no significant difference between males and females. Prevalence estimates varied significantly depending on the diagnostic criteria used (Global Initiative for Asthma: 6%; European Respiratory Society/American Thoracic Society: 1%; other: 3%). Because none of the examined studies were prospectively designed, incidence rates could not be determined.

Conclusions

This systematic review and meta-analysis provide the first robust assessment of severe asthma prevalence among European children. Our findings underscore the need for comprehensive research to address knowledge gaps in severe asthma, including determining incidence rates, standardising definitions, investigating regional differences and evaluating comorbidities and treatment strategies.




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Multicomponent services for symptoms in serious respiratory illness: a systematic review and meta-analysis

Background

People living with serious respiratory illness experience a high burden of symptoms. This review aimed to determine whether multicomponent services reduce symptoms in people with serious illness related to respiratory disease.

Methods

Electronic databases were searched to identify randomised controlled trials (RCTs) evaluating multicomponent services that enrolled patients due to symptoms, rather than underlying disease, and provided at least one nonpharmacological intervention. The primary outcome was chronic breathlessness and secondary outcomes were health-related quality of life (HRQoL), cough, fatigue and adverse events. At least two authors independently screened studies, assessed risk of bias and extracted data.

Results

Five RCTs, involving 439 patients, were included. In comparison to usual care, multicomponent services improved breathlessness mastery (Chronic Respiratory Questionnaire (CRQ) mastery scale, mean difference (MD) 0.43 points, 95% CI 0.20–0.67, three RCTs, 327 participants) and HRQoL (CRQ total score, MD 0.24 points, 95% CI 0.04–0.40, two RCTs, 237 participants). Fatigue did not improve with multicomponent services and no studies evaluated cough. No serious adverse events were reported. The one study evaluating mortality found increased survival in those accessing a multicomponent service. The certainty of evidence was very low, mainly due to detection and reporting bias.

Conclusion

Multicomponent services improve breathlessness mastery and HRQoL, with minimal risk. These findings support the use of multicomponent symptom-directed services for people living with serious respiratory illness.




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Opioids for the palliation of symptoms in people with serious respiratory illness: a systematic review and meta-analysis

Background

People living with serious respiratory illness experience a high burden of distressing symptoms. Although opioids are prescribed for symptom management, they generate adverse events, and their benefits are unclear.

Methods

We examined the efficacy and safety of opioids for symptom management in people with serious respiratory illness. Embase, MEDLINE and the Cochrane Central Register of Controlled Trials were searched up to 11 July 2022. Reports of randomised controlled trials administering opioids to treat symptoms in people with serious respiratory illness were included. Key exclusion criteria included <80% of participants having a nonmalignant lung disease. Data were extracted regarding study characteristics, outcomes of breathlessness, cough, health-related quality of life (HRQoL) and adverse events. Treatment effects were pooled using a generic inverse variance model with random effects. Risk of bias was assessed using the Cochrane Risk of Bias tool version 1.

Results

Out of 17 included trials, six were laboratory-based exercise trials (n=70), 10 were home studies measuring breathlessness in daily life (n=788) and one (n=18) was conducted in both settings. Overall certainty of evidence was "very low" to "low". Opioids reduced breathlessness intensity during laboratory exercise testing (standardised mean difference (SMD) –0.37, 95% CI –0.67– –0.07), but not breathlessness measured in daily life (SMD –0.10, 95% CI –0.64–0.44). No effects on HRQoL (SMD –0.42, 95% CI –0.98–0.13) or cough (SMD –1.42, 95% CI –3.99–1.16) were detected. In at-home studies, opioids led to increased frequency of nausea/vomiting (OR 3.32, 95% CI 1.70–6.51), constipation (OR 3.08, 95% CI 1.69–5.61) and drowsiness (OR 1.37, 95% CI 1.01–1.86), with serious adverse events including hospitalisation and death identified.

Conclusions

Opioids improved exertional breathlessness in laboratory exercise studies, but did not improve breathlessness, cough or HRQoL measured in daily life at home. There were significant adverse events, which may outweigh any benefits.




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Correlations of Long Noncoding RNA HNF4A-AS1 Alternative Transcripts with Liver Diseases and Drug Metabolism [Articles]

Hepatocyte nuclear factor 4 alpha antisense 1 (HNF4A-AS1) is a long noncoding RNA (lncRNA) gene physically located next to the transcription factor HNF4A gene in the human genome. Its transcription products have been reported to inhibit the progression of hepatocellular carcinoma (HCC) and negatively regulate the expression of cytochrome P450s (CYPs), including CYP1A2, 2B6, 2C9, 2C19, 2E1, and 3A4. By altering CYP expression, lncRNA HNF4A-AS1 also contributes to the susceptibility of drug-induced liver injury. Thus, HNF4A-AS1 lncRNA is a promising target for controlling HCC and modulating drug metabolism. However, HNF4A-AS1 has four annotated alternative transcripts in the human genome browsers, and it is unclear which transcripts the small interfering RNAs or small hairpin RNAs used in the previous studies are silenced and which transcripts should be used as the target. In this study, four annotated and two newly identified transcripts were confirmed. These six transcripts showed different expression levels in different liver disease conditions, including metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, and obesity. The expression patterns of all HNF4A-AS1 transcripts were further investigated in liver cell growth from human embryonic stem cells to matured hepatocyte-like cells, HepaRG differentiation, and exposure to rifampicin treatment. Several HNF4A-AS1 transcripts highly displayed correlations with these situations. In addition, some of the HNF4A-AS1 transcripts also showed a strong correlation with CYP3A4 during HepaRG maturation and rifampicin exposure. Our findings provide valuable insights into the specific roles of HNF4A-AS1 transcripts, paving the way for more targeted therapeutic strategies for liver diseases and drug metabolism.

SIGNIFICANCE STATEMENT

This study explores the alternative transcripts of HNF4A-AS1, showing how their expression changes in different biological conditions, from various liver diseases to the growth and differentiation of hepatocytes and drug metabolism. The generated knowledge is essential for understanding the independent roles of different transcripts from the same lncRNA in different liver diseases and drug metabolism situations.




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Investigations into the Concentrations and Metabolite Profiles of Doping Agents and Antidepressants in Human Seminal Fluid Using Liquid Chromatography-Mass Spectrometry [Articles]

Exogenous substances, including drugs and chemicals, can transfer into human seminal fluid and influence male fertility and reproduction. In addition, substances relevant in the context of sports drug testing programs, can be transferred into the urine of a female athlete (after unprotected sexual intercourse) and trigger a so-called adverse analytical finding. Here, the question arises as to whether it is possible to distinguish analytically between intentional doping offenses and unintentional contamination of urine by seminal fluid. To this end, 480 seminal fluids from nonathletes were analyzed to identify concentration ranges and metabolite profiles of therapeutic drugs that are also classified as doping agents. Therefore, a screening procedure was developed using liquid chromatography connected to a triple quadrupole mass spectrometer, and suspect samples (i.e., samples indicating the presence of relevant compounds) were further subjected to liquid chromatography-high-resolution accurate mass (tandem) mass spectrometry. The screening method yielded 90 findings (including aromatase inhibitors, selective estrogen receptor modulators, diuretics, stimulants, glucocorticoids, beta-blockers, antidepressants, and the nonapproved proliferator-activated receptor delta agonist GW1516) in a total of 81 samples, with 91% of these suspected cases being verified by the confirmation method. In addition to the intact drug, phase-I and -II metabolites were also occasionally observed in the seminal fluid. This study demonstrated that various drugs including those categorized as doping agents partition into seminal fluid. Monitoring substances and metabolites may contribute to a better understanding of the distribution and metabolism of exogenous substances in seminal fluid that may be responsible for the impairment of male fertility.

SIGNIFICANCE STATEMENT

This study demonstrates that doping agents as well as clinically relevant substances are transferred/eliminated into seminal fluid to a substantial extent and that knowledge about drug levels (and potential consequences for the male fertility and female exposure) is limited. The herein generated new dataset provides new insights into an important and yet little explored area of drug deposition and elimination, and hereby a basis for the assessment of contamination cases by seminal fluid in sports drug testing.




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Roles of the ABCG2 Transporter in Protoporphyrin IX Distribution and Toxicity [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II-Minireview]

ATP-binding cassette transporter subfamily G member 2 (ABCG2) is a membrane-bound transporter responsible for the efflux of various xenobiotics and endobiotics, including protoporphyrin IX (PPIX), an intermediate in the heme biosynthesis pathway. Certain genetic mutations and chemicals impair the conversion of PPIX to heme and/or increase PPIX production, leading to PPIX accumulation and toxicity. In mice, deficiency of ABCG2 protects against PPIX-mediated phototoxicity and hepatotoxicity by modulating PPIX distribution. In addition, in vitro studies revealed that ABCG2 inhibition increases the efficacy of PPIX-based photodynamic therapy by retaining PPIX inside target cells. In this review, we discuss the roles of ABCG2 in modulating the tissue distribution of PPIX, PPIX-mediated toxicity, and PPIX-based photodynamic therapy.

SIGNIFICANCE STATEMENT

This review summarized the roles of ABCG2 in modulating PPIX distribution and highlighted the therapeutic potential of ABCG2 inhibitors for the management of PPIX-mediated toxicity.




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Assessing Trends in Cytokine-CYP Drug Interactions and Relevance to Drug Dosing [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II-Minireview]

The regulation of drug-metabolizing enzymes and transporters by cytokines has been extensively studied in vitro and in clinic. Cytokine-mediated suppression of cytochrome P450 (CYP) or drug transporters may increase or decrease the systemic clearance of drug substrates that are primarily cleared via these pathways; neutralization of cytokines by therapeutic proteins may thereby alter systemic exposures of such drug substrates. The Food and Drug Administration recommends evaluating such clinical drug interactions during clinical development and has provided labeling recommendations for therapeutic proteins. To determine the clinical relevance of these drug interactions to dose adjustments, trends in steady-state exposures of CYP-sensitive substrates coadministered with cytokine modulators as reported in the University of Washington Drug Interaction Database were extracted and examined for each of the CYPs. Coadministration of cytochrome P450 family 3 subfamily A (CYP3A) (midazolam/simvastatin), cytochrome P450 subfamily 2C19 (omeprazole), or cytochrome P450 subfamily 1A2 (caffeine/tizanidine) substrates with anti-interleukin-6 and with anti-interleukin-23 therapeutics led to changes in systemic exposures of CYP substrates ranging from ~ –58% to ~35%; no significant trends were observed for cytochrome P450 subfamily 2D6 (dextromethorphan) and cytochrome P450 subfamily 2C9 (warfarin) substrates. Although none of these changes in systemic exposures have been reported as clinically meaningful, dose adjustment of midazolam for optimal sedation in acute care settings has been reported. Simulated concentration-time profiles of midazolam under conditions of elevated cytokine levels when coadministered with tocilizumab, suggest a ~six- to sevenfold increase in midazolam clearance, suggesting potential implications of cytokine–CYP drug interactions on dose adjustments of sensitive CYP3A substrates in acute care settings. Additionally, this article also provides a brief overview of nonclinical and clinical assessments of cytokine–CYP drug interactions in drug discovery and development.

SIGNIFICANCE STATEMENT

There has been significant progress in understanding cytokine-mediated drug interactions for CYP-sensitive substrates. This article provides an overview of the progress in this field, including a trend analysis of systemic exposures of CYP-sensitive substrates coadministered with anti-interleukin therapeutics. In addition, the review also provides a perspective of current methods used to assess these drug interactions during drug development and a focus on individualized medicine, particularly in acute care settings.




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Pharmacometabolomics in Drug Disposition, Toxicity, and Precision Medicine [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II-Minireview]

The precision medicine initiative has driven a substantial change in the way scientists and health care practitioners think about diagnosing and treating disease. While it has long been recognized that drug response is determined by the intersection of genetic, environmental, and disease factors, improvements in technology have afforded precision medicine guided dosing of drugs to improve efficacy and reduce toxicity. Pharmacometabolomics aims to evaluate small molecule metabolites in plasma and/or urine to help evaluate mechanisms that predict and/or reflect drug efficacy and toxicity. In this mini review, we provide an overview of pharmacometabolomic approaches and methodologies. Relevant examples where metabolomic techniques have been used to better understand drug efficacy and toxicity in major depressive disorder and cancer chemotherapy are discussed. In addition, the utility of metabolomics in drug development and understanding drug metabolism, transport, and pharmacokinetics is reviewed. Pharmacometabolomic approaches can help describe factors mediating drug disposition, efficacy, and toxicity. While important advancements in this area have been made, there remain several challenges that must be overcome before this approach can be fully implemented into clinical drug therapy.

SIGNIFICANCE STATEMENT

Pharmacometabolomics has emerged as an approach to identify metabolites that allow for implementation of precision medicine approaches to pharmacotherapy. This review article provides an overview of pharmacometabolomics including highlights of important examples.




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Characterizing the Distribution of a Stimulator of Interferon Genes Agonist and Its Metabolites in Mouse Liver by Matrix-Assisted Laser Desorption/Ionization Imaging Mass Spectrometry [Special Section on New and Emerging Areas and Technologies in Drug Met

A STING (stimulator of interferon genes) agonist GSK3996915 under investigation in early discovery for hepatitis B was orally dosed to a mouse model for understanding the parent drug distribution in liver, the target organ. Matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) was used to quantify the distribution of GSK3996915 in liver collected from mice administered a single oral dose at 90 mg/kg. GSK3996915 was detected with a zonal distribution localized in the portal triad and highly concentrated in the main bile ducts, indicating clearance through biliary excretion. High spatial resolution imaging showed the distribution of the parent drug localized to the cellular populations in the sinusoids, including the Kupffer cells. Additionally, a series of drug-related metabolites were observed to be localized in the central zones of the liver. These results exemplify the potential of utilizing MALDI IMS for measuring not only quantitative drug distribution and target exposure but also drug metabolism and elimination in a single suite of experiments.

SIGNIFICANCE STATEMENT

An integrated imaging approach utilizing matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) complemented with immunohistochemistry (IHC) and histology was used to address the question of target exposure at the cellular level. Localized quantification of the parent drug in the target organ and identification of potential metabolites in the context of tissue histology were also achieved in one experimental suite to support characterization of pharmacokinetic properties of the drug in the early discovery stage.:




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Evaluating Drug-Drug Interaction Risk Associated with Peptide Analogs Using advanced In Vitro Systems [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II]

Drug–drug interaction (DDI) assessment of therapeutic peptides is an evolving area. The industry generally follows DDI guidelines for small molecules, but the translation of data generated with commonly used in vitro systems to in vivo is sparse. In the current study, we investigated the ability of advanced human hepatocyte in vitro systems, namely HepatoPac, spheroids, and Liver-on-a-chip, to assess potential changes in regulation of CYP1A2, CYP2B6, CYP3A4, SLCO1B1, and ABCC2 in the presence of selected therapeutic peptides, proteins, and small molecules. The peptide NN1177, a glucagon and GLP-1 receptor co-agonist, did not suppress mRNA expression or activity of CYP1A2, CYP2B6, and CYP3A4 in HepatoPac, spheroids, or Liver-on-a-chip; these findings were in contrast to the data obtained in sandwich cultured hepatocytes. No effect of NN1177 on SLCO1B1 and ABCC2 mRNA was observed in any of the complex systems. The induction magnitude differed across the systems (e.g., rifampicin induction of CYP3A4 mRNA ranged from 2.8-fold in spheroids to 81.2-fold in Liver-on-a-chip). Small molecules, obeticholic acid and abemaciclib, showed varying responses in HepatoPac, spheroids, and Liver-on-a-chip, indicating a need for EC50 determinations to fully assess translatability data. HepatoPac, the most extensively investigated in this study (3 donors), showed high potential to investigate DDIs associated with CYP regulation by therapeutic peptides. Spheroids and Liver-on-a-chip were only assessed in one hepatocyte donor and further evaluations are required to confirm their potential. This study establishes an excellent foundation toward the establishment of more clinically-relevant in vitro tools for evaluation of potential DDIs with therapeutic peptides.

SIGNIFICANT STATEMENT

At present, there are no guidelines for drug–drug interaction (DDI) assessment of therapeutic peptides. Existing in vitro methods recommended for assessing small molecule DDIs do not appear to translate well for peptide drugs, complicating drug development for these moieties. Here, we establish evidence that complex cellular systems have potential to be used as more clinically-relevant tools for the in vitro DDI evaluation of therapeutic peptides.




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Exogenous Pregnane X Receptor Does Not Undergo Liquid-Liquid Phase Separation in Nucleus under Cell-Based In Vitro Conditions [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II]

Pregnane X receptor (PXR) belongs to the nuclear receptor superfamily that plays a crucial role in hepatic physiologic and pathologic conditions. Phase separation is a process in which biomacromolecules aggregate and condense into a dense phase as liquid condensates and coexist with a dilute phase, contributing to various cellular and biologic functions. Until now, whether PXR could undergo phase separation remains unclear. This study aimed to investigate whether PXR undergoes phase separation. Analysis of the intrinsically disordered regions (IDRs) using algorithm tools indicated a low propensity of PXR to undergo phase separation. Experimental assays such as hyperosmotic stress, agonist treatment, and optoDroplets assay demonstrated the absence of phase separation for PXR. OptoDroplets assay revealed the inability of the fusion protein of Cry2 with PXR to form condensates upon blue light stimulation. Moreover, phase separation of PXR did not occur even though the mRNA and protein expression levels of PXR target, cytochrome P450 3A4, changed after sorbitol treatment. In conclusion, for the first time, these findings suggested that exogenous PXR does not undergo phase separation following activation or under hyperosmotic stress in nucleus of cells.

SIGNIFICANCE STATEMENT

PXR plays a critical role in hepatic physiological and pathological processes. The present study clearly demonstrated that exogenous PXR does not undergo phase separation after activation by agonist or under hyperosmotic stress in nucleus. These findings may help understand PXR biology.




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Differential Tissue Abundance of Membrane-Bound Drug Metabolizing Enzymes and Transporter Proteins by Global Proteomics [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II]

Protein abundance data of drug-metabolizing enzymes and transporters (DMETs) are useful for scaling in vitro and animal data to humans for accurate prediction and interpretation of drug clearance and toxicity. Targeted DMET proteomics that relies on synthetic stable isotope-labeled surrogate peptides as calibrators is routinely used for the quantification of selected proteins; however, the technique is limited to the quantification of a small number of proteins. Although the global proteomics-based total protein approach (TPA) is emerging as a better alternative for large-scale protein quantification, the conventional TPA does not consider differential sequence coverage by identifying unique peptides across proteins. Here, we optimized the TPA approach by correcting protein abundance data by the sequence coverage, which was applied to quantify 54 DMETs for characterization of 1) differential tissue DMET abundance in the human liver, kidney, and intestine, and 2) interindividual variability of DMET proteins in individual intestinal samples (n = 13). Uridine diphosphate-glucuronosyltransferase 2B7 (UGT2B7), microsomal glutathione S-transferases (MGST1, MGST2, and MGST3) carboxylesterase 2 (CES2), and multidrug resistance-associated protein 2 (MRP2) were expressed in all three tissues, whereas, as expected, four cytochrome P450s (CYP3A4, CYP3A5, CYP2C9, and CYP4F2), UGT1A1, UGT2B17, CES1, flavin-containing monooxygenase 5, MRP3, and P-glycoprotein were present in the liver and intestine. The top three DMET proteins in individual tissues were: CES1>CYP2E1>UGT2B7 (liver), CES2>UGT2B17>CYP3A4 (intestine), and MGST1>UGT1A6>MGST2 (kidney). CYP3A4, CYP3A5, UGT2B17, CES2, and MGST2 showed high interindividual variability in the intestine. These data are relevant for enhancing in vitro to in vivo extrapolation of drug absorption and disposition and can be used to enhance the accuracy of physiologically based pharmacokinetic prediction of systemic and tissue concentration of drugs.

SIGNIFICANCE STATEMENT

This study quantified the abundance and compositions of drug-metabolizing enzymes and transporters in pooled human liver, intestine, and kidney microsomes as well as individual intestinal microsomes using an optimized global proteomics approach. The data revealed large intertissue differences in the abundance of these proteins and high intestinal interindividual variability in the levels of cytochrome P450s (e.g., CYP3A4 and CYP3A5), uridine diphosphate-glucuronosyltransferase 2B17, carboxylesterase 2, and microsomal glutathione S-transferase 2. These data are applicable for the prediction of first-pass metabolism and tissue-specific drug clearance.




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Regulation of Human Hydrolases and Its Implications in Pharmacokinetics and Pharmacodynamics [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II]

Hydrolases represent an essential class of enzymes indispensable for the metabolism of various clinically essential medications. Individuals exhibit marked differences in the expression and activation of hydrolases, resulting in significant variability in the pharmacokinetics (PK) and pharmacodynamics (PD) of drugs metabolized by these enzymes. The regulation of hydrolase expression and activity involves both genetic polymorphisms and nongenetic factors. This review examines the current understanding of genetic and nongenetic regulators of six clinically significant hydrolases, including carboxylesterase (CES)-1 CES2, arylacetamide deacetylase (AADAC), paraoxonase (PON)-1 PON3, and cathepsin A (CTSA). We explore genetic variants linked to the expression and activity of the hydrolases and their effects on the PK and PD of their substrate drugs. Regarding nongenetic regulators, we focus on the inhibitors and inducers of these enzymes. Additionally, we examine the developmental expression patterns and gender differences in the hydrolases when pertinent information was available. Many genetic and nongenetic regulators were found to be associated with the expression and activity of the hydrolases and PK and PD. However, hydrolases remain generally understudied compared with other drug-metabolizing enzymes, such as cytochrome P450s. The clinical significance of genetic and nongenetic regulators has not yet been firmly established for the majority of hydrolases. Comprehending the mechanisms that underpin the regulation of these enzymes holds the potential to refine therapeutic regimens, thereby enhancing the efficacy and safety of drugs metabolized by the hydrolases.

SIGNIFICANCE STATEMENT

Hydrolases play a crucial role in the metabolism of numerous clinically important medications. Genetic polymorphisms and nongenetic regulators can affect hydrolases’ expression and activity, consequently influencing the exposure and clinical outcomes of hydrolase substrate drugs. A comprehensive understanding of hydrolase regulation can refine therapeutic regimens, ultimately enhancing the efficacy and safety of drugs metabolized by the enzymes.




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50th Anniversary Celebration Collection Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part II--Editorial [Special Section on New and Emerging Areas and Technologies in Drug Metabolism and Disposition, Part




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Ketamine and Major Ketamine Metabolites Function as Allosteric Modulators of Opioid Receptors [Article]

Ketamine is a glutamate receptor antagonist that was developed over 50 years ago as an anesthetic agent. At subanesthetic doses, ketamine and some metabolites are analgesics and fast-acting antidepressants, presumably through targets other than glutamate receptors. We tested ketamine and its metabolites for activity as allosteric modulators of opioid receptors expressed as recombinant receptors in heterologous systems and with native receptors in rodent brain; signaling was examined by measuring GTP binding, β-arrestin recruitment, MAPK activation, and neurotransmitter release. Although micromolar concentrations of ketamine alone had weak agonist activity at μ opioid receptors, the combination of submicromolar concentrations of ketamine with endogenous opioid peptides produced robust synergistic responses with statistically significant increases in efficacies. All three opioid receptors (μ, , and ) showed synergism with submicromolar concentrations of ketamine and either methionine-enkephalin (Met-enk), leucine-enkephalin (Leu-enk), and/or dynorphin A17 (Dyn A17), albeit the extent of synergy was variable between receptors and peptides. S-ketamine exhibited higher modulatory effects compared with R-ketamine or racemic ketamine, with ~100% increase in efficacy. Importantly, the ketamine metabolite 6-hydroxynorketamine showed robust allosteric modulatory activity at μ opioid receptors; this metabolite is known to have analgesic and antidepressant activity but does not bind to glutamate receptors. Ketamine enhanced potency and efficacy of Met-enkephalin signaling both in mouse midbrain membranes and in rat ventral tegmental area neurons as determined by electrophysiology recordings in brain slices. Taken together, these findings support the hypothesis that some of the therapeutic effects of ketamine and its metabolites are mediated by directly engaging the endogenous opioid system.

SIGNIFICANCE STATEMENT

This study found that ketamine and its major biologically active metabolites function as potent allosteric modulators of μ, , and opioid receptors, with submicromolar concentrations of these compounds synergizing with endogenous opioid peptides, such as enkephalin and dynorphin. This allosteric activity may contribute to ketamine’s therapeutic effectiveness for treating acute and chronic pain and as a fast-acting antidepressant drug.




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Factors Influencing the Central Nervous System (CNS) Distribution of the Ataxia Telangiectasia Mutated and Rad3-Related Inhibitor Elimusertib (BAY1895344): Implications for the Treatment of CNS Tumors [Metabolism, Transport, and Pharmacogenetics]

Glioblastoma (GBM) is a disease of the whole brain, with infiltrative tumor cells protected by an intact blood-brain barrier (BBB). GBM has a poor prognosis despite aggressive treatment, in part due to the lack of adequate drug permeability at the BBB. Standard of care GBM therapies include radiation and cytotoxic chemotherapy that lead to DNA damage. Subsequent activation of DNA damage response (DDR) pathways can induce resistance. Various DDR inhibitors, targeting the key regulators of these pathways such as ataxia telangiectasia mutated and Rad3-related (ATR), are being explored as radio- and chemosensitizers. Elimusertib, a novel ATR kinase inhibitor, can prevent repair of damaged DNA, increasing efficacy of DNA-damaging cytotoxic therapies. Robust synergy was observed in vitro when elimusertib was combined with the DNA-damaging agent temozolomide; however, we did not observe improvement with this combination in in vivo efficacy studies in GBM orthotopic tumor-bearing mice. This in vitro–in vivo disconnect was explored to understand factors influencing central nervous system (CNS) distribution of elimusertib and reasons for lack of efficacy. We observed that elimusertib is rapidly cleared from systemic circulation in mice and would not maintain adequate exposure in the CNS for efficacious combination therapy with temozolomide. CNS distribution of elimusertib is partially limited by P-glycoprotein efflux at the BBB, and high binding to CNS tissues leads to low levels of pharmacologically active (unbound) drug in the brain. Acknowledging the potential for interspecies differences in pharmacokinetics, these data suggest that clinical translation of elimusertib in combination with temozolomide for treatment of GBM may be limited.

SIGNIFICANCE STATEMENT

This study examined the disconnect between the in vitro synergy and in vivo efficacy of elimusertib/temozolomide combination therapy by exploring systemic and central nervous system (CNS) distributional pharmacokinetics. Results indicate that the lack of improvement in in vivo efficacy in glioblastoma (GBM) patient-derived xenograft (PDX) models could be attributed to inadequate exposure of pharmacologically active drug concentrations in the CNS. These observations can guide further exploration of elimusertib for the treatment of GBM or other CNS tumors.




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Cardiac Neuroendocrine Tumor Metastases on 68Ga-DOTATATE PET/CT: Identification and Prognostic Significance

Neuroendocrine tumor (NET) metastases to the heart are found in 1%–4% of NET patients and have been reported primarily in the form of individual cases. We investigated the prevalence, clinical characteristics, imaging features, and outcomes of NET patients with cardiac metastases on 68Ga-DOTATATE PET/CT. Methods: 68Ga-DOTATATE PET/CT of 490 consecutive patients from a single institution were retrospectively reviewed for sites of metastases. The cumulative cardiovascular event rate and overall survival of patients with cardiac NET metastases (CNMs) were compared with those of a control group of metastatic NET patients without cardiac metastases. In patients with CNMs, the cardiac SUVmax with and without normalization to the myocardial background uptake was compared with a separate cohort of 11 patients with active cardiac sarcoidosis who underwent 68Ga-DOTATATE PET/CT for research purposes. Results: In total, 270 patients with metastatic NETs were identified, 9 (3.3%) of whom had CNMs. All 9 patients had grade 1–2 gastroenteropancreatic NETs, most commonly from the small intestine (7 patients). The control group consisted of 140 patients with metastatic grade 1–2 gastroenteropancreatic NETs. On Kaplan–Meier analysis, there was no significant difference in the risk of cardiovascular adverse events (P = 0.91 on log-rank test) or mortality (P = 0.83) between the metastatic NET patients with and without cardiac metastases. The degree of cardiac DOTATATE uptake was significantly higher in CNMs than in patients with cardiac sarcoidosis without overlap, in terms of both cardiac SUVmax (P = 0.027) and SUVmax–to–myocardial background ratio (P = 0.021). Conclusion: Routine 68Ga-DOTATATE PET/CT can be used to identify CNMs in 3% of patients with metastatic NETs. CNMs do not confer added cardiovascular or mortality risk. A distinguishing feature of CNMs is their high degree of DOTATATE uptake compared with focal myocardial inflammation.




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Efficacy and Toxicity of [177Lu]Lu-PSMA-617 for Metastatic Castration-Resistant Prostate Cancer: Results from the U.S. Expanded-Access Program and Comparisons with Phase 3 VISION Data

The phase 3 VISION trial demonstrated that [177Lu]Lu-PSMA-617 prolonged progression-free survival and overall survival (OS) in prostate-specific membrane antigen [PSMA]–positive metastatic castration-resistant prostate cancer (mCRPC) patients who progressed on taxane-based chemotherapy and androgen receptor–signaling inhibitors (ARSIs). The U.S. expanded-access program (EAP; NCT04825652) was opened to provide access to [177Lu]Lu-PSMA-617 for eligible patients until regulatory approval was obtained. This study aimed to evaluate the efficacy and safety profile of [177Lu]Lu-PSMA-617 within the EAP and compare the results with those from the VISION trial. Methods: Patients enrolled in the EAP at 4 institutions in the United States with available toxicity and outcome data were included. Outcome measures included OS, a prostate-specific antigen (PSA) response rate (RR) of at least 50%, and incidences of toxicity according to Common Terminology Criteria for Adverse Events version 5.0. Differences in baseline characteristics, outcome data, and toxicity between the EAP and VISION were evaluated using t testing of proportions and survival analyses. Results: In total, 117 patients with mCRPC who received [177Lu]Lu-PSMA-617 within the EAP between May 2021 and March 2022 were eligible and included in this analysis. Patients enrolled in the EAP were more heavily pretreated with ARSI (≥2 ARSI regimens: 70% vs. 46%; P < 0.001) and had worse performance status at baseline (Eastern Cooperative Oncology Group score ≥ 2: 19% vs. 7%; P < 0.001) than VISION patients. EAP and VISION patients had similar levels of grade 3 or higher anemia (18% vs. 13%; P = 0.15), thrombocytopenia (13% vs. 8%; P = 0.13), and neutropenia (3% vs. 3%; P = 0.85) and similar PSA RRs (42% vs. 46%; P = 0.50) and OS (median: 15.1 vs. 15.3 mo; P > 0.05). Conclusion: Patients with PSMA-positive mCRPC who received [177Lu]Lu-PSMA-617 within the EAP were later in their disease trajectory than VISION patients. Patients enrolled in the EAP achieved similar PSA RRs and OS and had a safety profile similar to that of the VISION trial patients.




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Initial Experience with [177Lu]Lu-PSMA-617 After Regulatory Approval for Metastatic Castration-Resistant Prostate Cancer: Efficacy, Safety, and Outcome Prediction

[177Lu]Lu-PSMA-617 was approved by the U.S. Food and Drug Administration for patients with prostate-specific membrane antigen (PSMA)–positive metastatic castration-resistant prostate cancer (mCRPC). Since the time of regulatory approval, however, real-world data have been lacking. This study investigated the efficacy, safety, and outcome predictors of [177Lu]Lu-PSMA-617 at a major U.S. academic center. Methods: Patients with mCRPC who received [177Lu]Lu-PSMA-617 at the Johns Hopkins Hospital outside clinical trials were screened for inclusion. Patients who underwent [177Lu]Lu-PSMA-617 and had available outcome data were included in this study. Outcome data included prostate-specific antigen (PSA) response (≥50% decline), PSA progression-free survival (PFS), and overall survival (OS). Toxicity data were evaluated according to the Common Terminology Criteria for Adverse Events version 5.03. The study tested the association of baseline circulating tumor DNA mutational status in homologous recombination repair, PI3K alteration pathway, and aggressive-variant prostate cancer–associated genes with treatment outcome. Baseline PSMA PET/CT images were analyzed using SelectPSMA, an artificial intelligence algorithm, to predict treatment outcome. Associations with the observed treatment outcome were evaluated. Results: All 76 patients with PSMA-positive mCRPC who received [177Lu]Lu-PSMA-617 met the inclusion criteria. A PSA response was achieved in 30 of 74 (41%) patients. The median PSA PFS was 4.1 mo (95% CI, 2.0–6.2 mo), and the median OS was 13.7 mo (95% CI, 11.3–16.1 mo). Anemia of grade 3 or greater, thrombocytopenia, and neutropenia were observed in 9 (12%), 3 (4%), and 1 (1%), respectively, of 76 patients. Transient xerostomia was observed in 23 (28%) patients. The presence of aggressive-variant prostate cancer–associated genes was associated with a shorter PSA PFS (median, 1.3 vs. 6.3 mo; P = 0.040). No other associations were observed between circulating tumor DNA mutational status and treatment outcomes. Eighteen of 71 (25%) patients classified by SelectPSMA as nonresponders had significantly lower rates of PSA response than patients classified as likely responders (6% vs. 51%; P < 0.001), a shorter PSA PFS (median, 1.3 vs. 6.3 mo; P < 0.001), and a shorter OS (median, 6.3 vs. 14.5 mo; P = 0.046). Conclusion: [177Lu]Lu-PSMA-617 offered in a real-world setting after regulatory approval in the United States demonstrated antitumor activity and a favorable toxicity profile. Artificial-intelligence–based analysis of baseline PSMA PET/CT images may improve patient selection. Validation of these findings on larger cohorts is warranted.




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Intrapatient Intermetastatic Heterogeneity Determined by Triple-Tracer PET Imaging in mCRPC Patients and Correlation to Survival: The 3TMPO Cohort Study

Intrapatient intermetastatic heterogeneity (IIH) has been demonstrated in metastatic castration-resistant prostate cancer (mCRPC) patients and is of the utmost importance for radiopharmaceutical therapy (RPT) eligibility. This study was designed to determine the prevalence of IIH and RPT eligibility in mCRPC patients through a triple-tracer PET imaging strategy. Methods: This was a multisite prospective observational study in which mCRPC patients underwent both 18F-FDG and 68Ga-prostate-specific membrane antigen (PSMA)–617 PET/CT scans. A third scan with 68Ga-DOTATATE, a potential biomarker of neuroendocrine differentiation, was performed if an 18F-FDG–positive/68Ga-PSMA–negative lesion was found. Per-tracer lesion positivity was defined as having an uptake at least 50% above that of the liver. IIH prevalence was defined as the percentage of participants having at least 2 lesions with discordant features on multitracer PET. Results: IIH was observed in 81 patients (82.7%), and at least 1 18F-FDG–positive/68Ga-PSMA–negative lesion was found in 45 patients (45.9%). Of the 37 participants who also underwent 68Ga-DOTATATE PET/CT, 6 (16.2%) had at least 1 68Ga-DOTATATE–positive lesion. In total, 12 different combinations of lesion imaging phenotypes were observed. On the basis of our prespecified criteria, 52 (53.1%) participants were determined to be eligible for PSMA RPT, but none for DOTATATE RPT. Patients with IIH had a significantly shorter median overall survival than patients without IIH (9.5 mo vs. not reached; log-rank P = 0.03; hazard ratio, 2.7; 95% CI, 1.1–6.8). Conclusion: Most mCRPC patients showed IIH, which was associated with shorter overall survival. On the basis of a triple-tracer PET approach, multiple phenotypic combinations were found. Correlation of these imaging phenotypes with genomics and treatment response will be relevant for precision medicine.




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Impact of 18F-FES PET/CT on Clinical Decisions in the Management of Recurrent or Metastatic Breast Cancer

The clinical impact of 16α-18F-fluoro-17β-estradiol (18F-FES) PET/CT on patient management has not been well investigated. The aim of this study was to assess the clinical impact of 18F-FES PET/CT on the management of patients with recurrent or metastatic breast cancer. Methods: Study subjects were identified retrospectively from a database of a prospective trial for postmarketing surveillance of 18F-FES between 2021 and 2023. Patients who were suspected or known to have recurrent or metastatic estrogen receptor–positive breast cancer based on a routine standard workup were included. Planned management before and actual management after 18F-FES PET/CT were assessed by 2 experienced medical oncologists via medical chart review. A 5-point questionnaire was provided to evaluate the value of 18F-FES PET/CT for management planning. The rate of intention-to-treat and interdisciplinary changes, and the impact of 18F-FES PET/CT according to PET/CT result or clinical indication, were examined. Results: Of the 344 included patients, 120 (35%) experienced a change in management after 18F-FES PET/CT. In 139 (40%) patients,18F-FES PET/CT supported the existing management decision without a change in management. Intention-to-treat and interdisciplinary changes accounted for 64% (77/120) and 68% (82/120) of all changes, respectively. A higher rate of change was observed when lesions were 18F-FES–negative (44% [36/81]) than 18F-FES–positive (30% [51/172]) or mixed 18F-FES–positive/negative (36% [33/91]). Regarding clinical indications, the highest rate of change was shown when evaluating the origins of metastasis of double primary cancers (64% [9/14]). Conclusion: 18F-FES PET/CT modified the management of recurrent or metastatic breast cancer, serving as an impactful imaging modality in clinical practice.




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Bile Acid Signaling in Metabolic and Inflammatory Diseases and Drug Development [Review Article]

Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates biliary secretion of lipids, endogenous metabolites, and xenobiotics. In intestine, bile acids facilitate the digestion and absorption of dietary lipids and fat-soluble vitamins. Through activation of nuclear receptors and G protein-coupled receptors and interaction with gut microbiome, bile acids critically regulate host metabolism and innate and adaptive immunity and are involved in the pathogenesis of cholestasis, metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, type-2 diabetes, and inflammatory bowel diseases. Bile acids and their derivatives have been developed as potential therapeutic agents for treating chronic metabolic and inflammatory liver diseases and gastrointestinal disorders.

Significance Statement

Bile acids facilitate biliary cholesterol solubilization and dietary lipid absorption, regulate host metabolism and immunity, and modulate gut microbiome. Targeting bile acid metabolism and signaling holds promise for treating metabolic and inflammatory diseases.




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Roles of Individual Human Cytochrome P450 Enzymes in Drug Metabolism [Review Article]

Our knowledge of the roles of individual cytochrome P450 (P450) enzymes in drug metabolism has developed considerably in the past 30 years, and this base has been of considerable use in avoiding serious issues with drug interactions and issues due to variations. Some newer approaches are being considered for "phenotyping" metabolism reactions with new drug candidates. Endogenous biomarkers are being used for noninvasive estimation of levels of individual P450 enzymes. There is also the matter of some remaining "orphan" P450s, which have yet to be assigned reactions. Practical problems that continue in drug development include predicting drug-drug interactions, predicting the effects of polymorphic and other P450 variations, and evaluating interspecies differences in drug metabolism, particularly in the context of "metabolism in safety testing" regulatory issues ["disproportionate (human) metabolites"].

Significance Statement

Cytochrome P450 enzymes are the major catalysts involved in drug metabolism. The characterization of their individual roles has major implications in drug development and clinical practice.