The human major histocompatibility complex (MHC) is a ~4 Mb genomic segment on Chromosome 6 that plays a pivotal role in the immune response. Despite its importance in various traits and diseases, its complex nature makes it challenging to accurately characterize on a routine basis. We present a novel approach allowing targeted sequencing and de novo haplotypic assembly of the MHC region in heterozygous samples, using long-read sequencing technologies. Our approach is validated using two reference samples, two family trios, and an African-American sample. We achieved excellent coverage (96.6%–99.9% with at least 30x depth) and high accuracy (99.89%–99.99%) for the different haplotypes. This methodology offers a reliable and cost-effective method for sequencing and fully characterizing the MHC without the need for whole-genome sequencing, facilitating broader studies on this important genomic segment and having significant implications in immunology, genetics, and medicine.

The 10q11.22 chromosomal region is a duplication-rich interval of the human genome and one of the last to be fully assembled. It carries copy number–variable genes associated with intellectual disability, bipolar disorder, and obesity. In this study, we characterized the structural diversity at this locus by analyzing 64 haploid assemblies produced by the Human Pangenome Reference Consortium. We identified 11 alternative haplotypes that differ in the copy number and/or orientation of large genomic segments, ranging from hundreds of kilobase pairs (kbp) to over one megabase pair (Mbp). We uncovered a 2.4 Mbp size difference between the shortest and longest haplotypes. Breakpoint analysis revealed that genomic instability results from nonallelic homologous recombination between segmental duplication (SD) pairs with varying similarity (94.4%–99.6%). Nonetheless, these pairs generally recombine at positions where their identity is higher (>99.6%). Recurrent inversions occur with different breakpoints within the same inverted SD pair. Inversion polymorphisms shuffle the entire SD arrangement, creating new predispositions to copy-number variations. The SD architecture is associated with a catarrhine-specific subgroup of the AGAP gene family, which likely triggered the accumulation of SDs at this locus over the past 25 million years of human evolution. Our results reveal extensive structural diversity and genomic instability at the 10q11.22 locus, and expand the general understanding of the mutational mechanisms behind SD-mediated rearrangements.

The rising obesity epidemic is a phenomenon that has gained increasing attention from health providers and health policy makers. This led to recognition of nonalcoholic fatty liver disease (MASLD). The standard for its assessment has been histologic, which is neither practical nor acceptable by patients. Subsequently, a number of noninvasive assessment methods have been developed. However, despite ease of implementation, their confounding variables do hinder their accuracy. Nonetheless, the development of the liver stiffness measurement (LSM) and incorporation of other biological parameters has minimized but not eliminated the need for liver biopsy. Imaging methods are useful in evaluation, estimation, and following the progression of steatosis and fibrosis with particular attention to controlled attenuation parameter (CAP) and MRI–Proton Density Fat Fraction (MRI-PDFF). The choices for the family physician are broad and rely on tests’ availability, cost, and patient acceptance. Great efforts have been undertaken to produce more robust and novel noninvasive markers that indicate fibrinogenesis directly in an implementable and cost-effective way.

Introduction:

High-quality primary care can reduce avoidable emergency department visits and emergency hospitalizations. The availability of electronic medical record (EMR) data and capacities for data storage and processing have created opportunities for predictive analytics. This systematic review examines studies which predict emergency department visits, hospitalizations, and mortality using EMR data from primary care.

BACKGROUND:Practice on fasting prior to extubation in critically ill patients is variable. Efficacy of fasting in reducing gastric volume has not been well established. The primary objective of this study was to assess the effect of 4 h of fasting on prevalence of empty stomach using gastric ultrasonography in critically ill subjects who are fasted for extubation. The secondary objectives were to evaluate the change in gastric volumes during 4 h of fasting and to determine factors associated with empty stomach after fasting.METHODS:This was a single-center, prospective, observational study on adult ICU subjects who were enterally fed for at least 6 h continuously and mechanically ventilated. Gastric ultrasound was performed immediately prior to commencement of fasting, after 4 h of fasting, and after nasogastric (NG) aspiration after 4 h of fasting. An empty stomach was defined as a gastric volume ≤ 1.5 mL/kg.RESULTS:Forty subjects were recruited, and 38 (95%) had images suitable for analysis. The prevalence of empty stomach increased after 4 h of fasting (25 [65.8%] vs 31 [81.6%], P = .041) and after 4 h of fasting with NG aspiration (25 [65.8%] vs 34 [89.5%], P = .008). There was a significant difference in median (interquartile range) gastric volume per body weight between before fasting and 4 h after fasting (1.0 [0.5–1.8] mL/kg vs 0.4 [0.2–1.0] mL/kg, P < .001). No patient factors were associated with higher prevalence of empty stomach after 4 h of fasting.CONCLUSIONS:Most mechanically ventilated subjects had empty stomachs prior to fasting for extubation. Fasting for 4 h further increased the prevalence of empty stomach at extubation to > 80%.

BACKGROUND:Beneficial effects of breathing at FIO2 < 0.21 on disease outcomes have been reported in previous preclinical and clinical studies. However, the safety and intra-hospital feasibility of breathing hypoxic gas for 5 d have not been established. In this study, we examined the physiologic effects of breathing a gas mixture with FIO2 as low as 0.11 in 5 healthy volunteers.METHODS:All 5 subjects completed the study, spending 5 consecutive days in a hypoxic tent, where the ambient oxygen level was lowered in a stepwise manner over 5 d, from FIO2 of 0.16 on the first day to FIO2 of 0.11 on the fifth day of the study. All the subjects returned to an environment at room air on the sixth day. The subjects' SpO2, heart rate, and breathing frequency were continuously recorded, along with daily blood sampling, neurologic evaluations, transthoracic echocardiography, and mental status assessments.RESULTS:Breathing hypoxia concentration dependently caused profound physiologic changes, including decreased SpO2 and increased heart rate. At FIO2 of 0.14, the mean SpO2 was 92%; at FIO2 of 0.13, the mean SpO2 was 93%; at FIO2 of 0.12, the mean SpO2 was 88%; at FIO2 of 0.11, the mean SpO2 was 85%; and, finally, at an FIO2 of 0.21, the mean SpO2 was 98%. These changes were accompanied by increased erythropoietin levels and reticulocyte counts in blood. All 5 subjects concluded the study with no adverse events. No subjects exhibited signs of mental status changes or pulmonary hypertension.CONCLUSIONS:Results of the current physiologic study suggests that, within a hospital setting, delivering FIO2 as low as 0.11 is feasible and safe in healthy subjects, and provides the foundation for future studies in which therapeutic effects of hypoxia breathing are tested.

A prefilled syringe (PFS) should be able to be adequately and consistently extruded during injection for optimal safe drug delivery and accurate dosing. To facilitate appropriate break-loose and gliding forces (BLGFs) required during injection, certain primary packaging materials (PPMs) such as the syringe barrel and plunger are usually coated with silicone oil, which acts as a lubricant. Due to its direct contact with drug, silicone oil can increase the number of particles in the syringe, which could lead to adverse interactions. Compliance with regulatory-defined silicone oil quantities in certain drug products, such as ophthalmics, presents a trade-off with the necessity for desirable low and consistent BLGF. In addition to its siliconization, the dimensional accuracy of the PPM has an important role in controlling the BLGF. The dimensions of the PPM are individualized depending on the product and its design and have certain tolerances that must be met during manufacturing. Most studies on ophthalmics focused on the adverse interactions between silicone oil and the drug. To the authors' knowledge, there have been no public studies so far that have investigated the impact of the dimensional variability of the PPM on the BLGF in ophthalmic PFSs. In this study, we applied advanced optical shaft and tactile measuring technologies to investigate this impact. The syringes investigated were first sampled during aseptic production and tested for the BLGF. Subsequently, defined dimensions of the PPM were measured individually. The results showed that the dimensional variability of the PPM can have a negative impact on the BLGF, despite their conformity to specifications, which indicates that the currently available market quality of PPMs is improvable for critical drug products such as ophthalmics. This study could serve as an approach to define product-specific requirements for primary packaging combinations and thus appropriate specifications based on data during the development stage of drug products.

Long noncoding (lnc)RNAs emerge as regulators of genome stability. The nuclear-enriched abundant transcript 1 (NEAT1) is overexpressed in many tumors and is responsive to genotoxic stress. However, the mechanism that links NEAT1 to DNA damage response (DDR) is unclear. Here, we investigate the expression, modification, localization, and structure of NEAT1 in response to DNA double-strand breaks (DSBs). DNA damage increases the levels and N6-methyladenosine (m⁶A) marks on NEAT1, which promotes alterations in NEAT1 structure, accumulation of hypermethylated NEAT1 at promoter-associated DSBs, and DSB signaling. The depletion of NEAT1 impairs DSB focus formation and elevates DNA damage. The genome-protective role of NEAT1 is mediated by the RNA methyltransferase 3 (METTL3) and involves the release of the chromodomain helicase DNA binding protein 4 (CHD4) from NEAT1 to fine-tune histone acetylation at DSBs. Our data suggest a direct role for NEAT1 in DDR.

During B-cell development, cells progress through multiple developmental stages, with the pro-B-cell stage defining commitment to the B-cell lineage. YY1 is a ubiquitous transcription factor that is capable of both activation and repression functions. We found here that knockout of YY1 at the pro-B-cell stage eliminates B lineage commitment. YY1 knockout pro-B cells can generate T lineage cells in vitro using the OP9-DL4 feeder system and in vivo after injection into sublethally irradiated Rag1^–/– mice. These T lineage-like cells lose their B lineage transcript profile and gain a T-cell lineage profile. Single-cell RNA-seq experiments showed that as YY1 knockout pro-B cells transition into T lineage cells in vitro, various cell clusters adopt transcript profiles representing a multiplicity of hematopoietic lineages, indicating unusual lineage plasticity. In addition, YY1 KO pro-B cells in vivo can give rise to other hematopoietic lineages in vivo. Evaluation of RNA-seq, scRNA-seq, ChIP-seq, and scATAC-seq data indicates that YY1 controls numerous chromatin-modifying proteins leading to increased accessibility of alternative lineage genes in YY1 knockout pro-B cells. Given the ubiquitous nature of YY1 and its dual activation and repression functions, YY1 may regulate commitment in multiple cell lineages.

Animal germline development and fertility rely on paralogs of general transcription factors that recruit RNA polymerase II to ensure cell type-specific gene expression. It remains unclear whether gene expression processes downstream from such paralog-based transcription is distinct from that of canonical RNA polymerase II genes. In Drosophila, the testis-specific TBP-associated factors (tTAFs) activate over a thousand spermatocyte-specific gene promoters to enable meiosis and germ cell differentiation. Here, we show that efficient termination of tTAF-activated transcription relies on testis-specific paralogs of canonical polymerase-associated factor 1 complex (PAF1C) proteins, which form a testis-specific PAF1C (tPAF). Consequently, tPAF mutants show aberrant expression of hundreds of downstream genes due to read-in transcription. Furthermore, tPAF facilitates expression of Y-linked male fertility factor genes and thus serves to maintain spermatocyte-specific gene expression. Consistently, tPAF is required for the segregation of meiotic chromosomes and male fertility. Supported by comparative in vivo protein interaction assays, we provide a mechanistic model for the functional divergence of tPAF and the PAF1C and identify transcription termination as a developmentally regulated process required for germline-specific gene expression.

Cellular plasticity in adult multicellular organisms is a protective mechanism that allows certain tissues to regenerate in response to injury. Considering that aging involves exposure to repeated injuries over a lifetime, it is conceivable that cell identity itself is more malleable—and potentially erroneous—with age. In this review, we summarize and critically discuss the available evidence that cells undergo age-related shifts in identity, with an emphasis on those that contribute to age-associated pathologies, including neurodegeneration and cancer. Specifically, we focus on reported instances of programs associated with dedifferentiation, biased differentiation, acquisition of features from alternative lineages, and entry into a preneoplastic state. As some of the most promising approaches to rejuvenate cells reportedly also elicit transient changes to cell identity, we further discuss whether cell state change and rejuvenation can be uncoupled to yield more tractable therapeutic strategies.

Neural reflexes occupy a central role in physiological homeostasis. The vagus nerve is a major conduit for transmitting afferent and efferent signals in homeostatic reflex arcs between the body and the brain. Recent advances in neuroscience, immunology, and physiology have revealed important vagus nerve mechanisms in suppressing inflammation and treating rheumatoid arthritis and other autoimmune conditions. Numerous clinical trials indicate that there is significant benefit to vagus nerve stimulation therapy. Although many questions are still unanswered, it will be important, even necessary, to pursue answers that will be useful in guiding interventions to modulate immunological and physiological homeostasis.

Caenorhabditis elegans is an important model organism for human health and disease, with foundational contributions to the understanding of gene expression and tissue patterning in animals. An invaluable tool in modern gene expression research is the presence of a high-resolution ribosome structure, though no such structure exists for C. elegans. Here, we present a high-resolution single-particle cryogenic electron microscopy (cryo-EM) reconstruction and molecular model of a C. elegans ribosome, revealing a significantly streamlined animal ribosome. Many facets of ribosome structure are conserved in C. elegans, including overall ribosomal architecture and the mechanism of cycloheximide, whereas other facets, such as expansion segments and eL28, are rapidly evolving. We identify uL5 and uL23 as two instances of tissue-specific ribosomal protein paralog expression conserved in Caenorhabditis, suggesting that C. elegans ribosomes vary across tissues. The C. elegans ribosome structure will provide a basis for future structural, biochemical, and genetic studies of translation in this important animal system.

Bacterial regulatory RNAs (sRNAs) are important players to control gene expression. In Staphylococcus aureus, SprC is an antivirulent trans-acting sRNA known to base-pair with the major autolysin atl mRNA, preventing its translation. Using MS2-affinity purification coupled with RNA sequencing, we looked for its sRNA-RNA interactome and identified 14 novel mRNA targets. In vitro biochemical investigations revealed that SprC binds two of them, czrB and deoD, and uses a single accessible region to regulate its targets, including Atl translation. Unlike Atl regulation, the characterization of the SprC-czrB interaction pinpointed a destabilization of the czrAB cotranscript, leading to a decrease of the mRNA level that impaired CzrB zinc efflux pump expression. On a physiological standpoint, we showed that SprC expression is detrimental to combat against zinc toxicity. In addition, phagocyctosis assays revealed a significant, but moderate, increase of czrB mRNA levels in a sprC-deleted mutant, indicating a functional link between SprC and czrB upon internalization in macrophages, and suggesting a role in resistance to both oxidative and zinc bursts. Altogether, our data uncover a novel pathway in which SprC is implicated, highlighting the multiple strategies used by S. aureus to balance virulence using an RNA regulator.

Background

Recently, cough reflex hypersensitivity has been proposed as a common underlying feature of chronic cough in adults. However, symptoms and clinical characteristics of cough hypersensitivity have not been studied amongst phenotypes of chronic cough. This study aimed to compare symptom features, such as cough triggers and associated throat sensations, of cough hypersensitivity in patients with asthmatic chronic cough and those with refractory chronic cough (RCC).

Extract

It is of utmost importance that medicines are available at all times for our patients. Historically, medication unavailability has typically, if not exclusively, affected low- and middle-income countries [1]. More recently however, drug shortages have also been reported in high-income European countries [2]. Drug shortages have negative health consequences for patients [3], and a profound economic impact, with the need to resort to more expensive alternatives and demands on healthcare professionals’ time to find, prescribe and dispense alternatives [4].

Extract

In cystic fibrosis (CF), Pseudomonas aeruginosa acquisition represents a turning point in disease progression. The presence of chronic P. aeruginosa infection is associated with worsening lung function and increased risk of earlier death, whereas treatment substantially improves lung function and survival [1, 2]. Efforts to diagnose and eradicate early P. aeruginosa provide lasting benefits for children with CF [3, 4]. However, the timing of infection varies considerably between individuals with CF, treatment centres [5, 6], and different birth cohorts of people with the disease [7, 8].

Background

Pseudomonas aeruginosa is a common pathogen that contributes to progressive lung disease in cystic fibrosis (CF). Genetic factors other than CF-causing CFTR (CF transmembrane conductance regulator) variations contribute ~85% of the variation in chronic P. aeruginosa infection age in CF according to twin studies, but the susceptibility loci remain unknown. Our objective is to advance understanding of the genetic basis of host susceptibility to P. aeruginosa infection.

Background

Halm's clinical stability criteria have long guided antibiotic treatment and hospital discharge decisions for patients hospitalised with community-acquired pneumonia (CAP). Originally introduced in 1998, these criteria were established based on a relatively small and select patient population. Consequently, our study aims to reassess their applicability in the management of CAP in a contemporary real-world setting.

Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 are important hepatic transporters. We previously identified OATP1B3 being critically implicated in the disposition of abiraterone. We aimed to further investigate the effects of abiraterone on the activities of OATP1B1 and OATP1B3 utilizing a validated endogenous biomarker coproporphyrin I (CP-I). We used OATP1B-transfected cells to characterize the inhibitory potential of abiraterone against OATP1B-mediated uptake of CP-I. Inhibition constant (K_i) was incorporated into our physiologically based pharmacokinetic (PBPK) modeling to simulate the systemic exposures of CP-I among cancer populations receiving either our model-informed 500 mg or clinically approved 1000 mg abiraterone acetate (AA) dosage. Simulated data were compared with clinical CP-I concentrations determined among our nine metastatic prostate cancer patients receiving 500 mg AA treatment. Abiraterone inhibited OATP1B3-mediated, but not OATP1B1-mediated, uptake of CP-I in vitro, with an estimated K_i of 3.93 μM. Baseline CP-I concentrations were simulated to be 0.81 ± 0.26 ng/ml and determined to be 0.72 ± 0.16 ng/ml among metastatic prostate cancer patients, both of which were higher than those observed for healthy subjects. PBPK simulations revealed an absence of OATP1B3-mediated interaction between abiraterone and CP-I. Our clinical observations confirmed that CP-I concentrations remained comparable to baseline levels up to 12 weeks post 500 mg AA treatment. Using CP-I as an endogenous biomarker, we identified the inhibition of abiraterone on OATP1B3 but not OATP1B1 in vitro, which was predicted and observed to be clinically insignificant. We concluded that the interaction risk between AA and substrates of OATP1Bs is low.

In this study, the nonclinical pharmacokinetics of OLX702A-075-16, an RNA interference therapeutic currently in development, were investigated. OLX702A-075-16 is a novel N-acetylgalactosamine conjugated asymmetric small-interfering RNA (GalNAc-asiRNA) used for the treatment of an undisclosed liver disease. Its unique 16/21-mer asymmetric structure reduces nonspecific off-target effects without compromising efficacy. We investigated the plasma concentration, tissue distribution, metabolism, and renal excretion of OLX702A-075-16 following a subcutaneous administration in mice and rats. For bioanalysis, high-performance liquid chromatography with fluorescence detection was used. The results showed rapid clearance from plasma (0.5 to 1.5 hours of half-life) and predominant distribution to the liver and/or kidney. Less than 1% of the liver concentration of OLX702A-075-16 was detected in the other tissues. Metabolite profiling using liquid chromatography coupled with high-resolution mass spectrometry revealed that the intact duplex OLX702A-075-16 was the major compound in plasma. The GalNAc moiety was predominantly metabolized from the sense strand in the liver, with the unconjugated sense strand of OLX702A-075-16 accounting for more than 95% of the total exposure in the rat liver. Meanwhile, the antisense strand was metabolized by the sequential loss of nucleotides from the 3'-terminus by exonuclease, with the rat liver samples yielding the most diverse truncated forms of metabolites. Urinary excretion over 96 hours was less than 1% of the administered dose in rats. High plasma protein binding of OLX702A-075-16 likely inhibited its clearance through renal filtration.

Organic anion transporting polypeptides (OATP, gene symbol SLCO) are well-recognized key determinants for the absorption, distribution, and excretion of a wide spectrum of endogenous and exogenous compounds including many antineoplastic agents. It was therefore proposed as a potential drug target for cancer therapy. In our previous study, it was found that low-dose X-ray and carbon ion irradiation both upregulated the expression of OATP family member OATP1A2 and in turn, led to a more dramatic killing effect when cancer cells were cotreated with antitumor drugs such as methotrexate. In the present study, the underlying mechanism of the phenomenon was explored in breast cancer cell line MCF-7. It was found that the nonreceptor tyrosine kinase v-YES-1 Yamaguchi sarcoma viral oncogene homolog 1 (YES-1) was temporally coordinated with the change of OATP1A2 after irradiation. The overexpression of YES-1 significantly increased OATP1A2 both at the mRNA and protein level. The signal transducer and activator of transcription 3 (STAT3) pathway is likely the downstream target of YES-1 because phosphorylation and nuclear accumulation of STAT3 were both enhanced after overexpressing YES-1 in MCF-7 cells. Further investigation revealed that there are two possible binding sites of STAT3 localized at the upstream sequence of SLCO1A2, the encoding gene of OATP1A2. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis suggested that these two sites bound to STAT3 specifically and the overexpression of YES-1 significantly increased the association of the transcription factor with the putative binding sites. Finally, inhibition or knockdown of YES-1 attenuated the induction effect of radiation on the expression of OATP1A2.

The CYP3A7 enzyme accounts for ~50% of the total cytochrome P450 (P450) content in fetal and neonatal livers and is the predominant P450 involved in neonatal xenobiotic metabolism. Additionally, it is a key player in healthy birth outcomes through the oxidation of dehydroepiandrosterone (DHEA) and DHEA-sulfate. The amount of the other hepatic CYP3A isoforms, CYP3A4 and CYP3A5, expressed in neonates is low but highly variable, and therefore the activity of individual CYP3A isoforms is difficult to differentiate due to their functional similarities. Consequently, a better understanding of the contribution of CYP3A7 to drug metabolism is essential to identify the risk that drugs may pose to neonates and developing infants. To distinguish CYP3A7 activity from CYP3A4/5, we sought to further characterize the selectivity of the specific CYP3A inhibitors CYP3cide, clobetasol, and azamulin. We used three substrate probes, dibenzylfluorescein, luciferin-PPXE, and midazolam, to determine the IC₅₀ and metabolism-dependent inhibition (MDI) properties of the CYP3A inhibitors. Probe selection had a significant effect on the IC₅₀ values and P450 inactivation across all inhibitory compounds and enzymes. CYP3cide and azamulin were both identified as MDIs and were most specific for CYP3A4. Contrary to previous reports, we found that clobetasol propionate (CP) was not an MDI of CYP3A5 but was more selective for CYP3A5 over CYP3A4/7. We further investigated CYP3cide and CP’s ability to differentiate CYP3A7 activity in an equal mixture of recombinant CYP3A4, CYP3A5, and CYP3A7, and our results provide confidence of CYP3cide’s and CP’s ability to distinguish CYP3A7 activity in the presence of the other CYP3A isoforms.

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.

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.

The -aminobutyric acid type A (GABA_A) receptor is modulated by a number of neuroactive steroids. Sulfated steroids and 3β-hydroxy steroids inhibit, while 3α-hydroxy steroids typically potentiate the receptor. Here, we have investigated inhibition of the α1β32L GABA_A receptor by the endogenous neurosteroid 3α-hydroxy-5β-pregnan-20-one (3α5βP) and the synthetic neuroactive steroid 3α-hydroxy-5α-androstane-17β-carbonitrile (ACN). The receptors were expressed in Xenopus oocytes. All experiments were done using two-electrode voltage-clamp electrophysiology. In the presence of low concentrations of GABA, 3α5βP and ACN potentiate the GABA_A receptor. To reveal inhibition, we conducted the experiments on receptors activated by the combination of a saturating concentration of GABA and propofol to fully activate the receptors and mask potentiation, or on mutant receptors in which potentiation is ablated. Under these conditions, both steroids inhibited the receptor with IC₅₀s of ~13 μM and maximal inhibitory effects of 70–90%. Receptor inhibition by 3α5βP was sensitive to substitution of the α1 transmembrane domain (TM) 2-2' residue, previously shown to ablate inhibition by pregnenolone sulfate. However, results of coapplication studies and the apparent lack of state dependence suggest that pregnenolone sulfate and 3α5βP inhibit the GABA_A receptor independently and through distinct mechanisms. Mutations to the neurosteroid binding sites in the α1 and β3 subunits statistically significantly, albeit weakly and incompletely, reduced inhibition by 3α5βP and ACN.

The antitumor effect of cardiotonic steroids (CTS) has stimulated the search for new methods to evaluate both kinetic and thermodynamic aspects of their binding to Na⁺/K⁺-ATPase (IUBMB Enzyme Nomenclature). We propose a real-time assay based on a chromogenic substrate for phosphatase activity (pNPPase activity), using only two concentrations with an inhibitory progression curve, to obtain the association rate (k_on), dissociation rate (k_off), and equilibrium (K_i) constants of CTS for the structure-kinetics relationship in drug screening. We show that changing conditions (from ATPase to pNPPase activity) resulted in an increase of K_i of the cardenolides digitoxigenin, essentially due to a reduction of k_on. In contrast, the K_i of the structurally related bufadienolide bufalin increased much less due to the reduction of its k_off partially compensating the decrease of its k_on. When evaluating the kinetics of 15 natural and semisynthetic CTS, we observed that both k_on and k_off correlated with K_i (Spearman test), suggesting that differences in potency depend on variations of both k_on and k_off. A rhamnose in C3 of the steroidal nucleus enhanced the inhibitory potency by a reduction of k_off rather than an increase of k_on. Raising the temperature did not alter the k_off of digitoxin, generating a H (k_off) of –10.4 ± 4.3 kJ/mol, suggesting a complex dissociation mechanism. Based on a simple and inexpensive methodology, we determined the values of k_on, k_off, and K_i of the CTS and provided original kinetics and thermodynamics differences between CTS that could help the design of new compounds.

ABSTRACTDespite global consensus on the importance of male involvement in family planning, disparities persist in low- and middle-income countries, where women continue to bear the responsibility for these initiatives. The Philippines, with a high fertility rate and unmet family planning needs, exemplifies this challenge. We present the experiences and lessons learned from implementing the no-scalpel vasectomy (NSV) program in Davao City, showcasing its potential for increasing male engagement in family planning decisions. Launched in 2008, the program aimed to address gender disparity by promoting NSV as a safe and effective contraceptive alternative to female-centric methods. Through the use of culturally sensitive information campaigns and couple-focused counseling, the program challenged traditional notions of masculinity and encouraged shared decision-making. Strong local government commitment and public-private partnerships played key roles in driving the program’s success. Results showed an average annual increase of 80% in NSV clients over the past 3 years compared to before the COVID-19 pandemic, underscoring its effectiveness. The program presents a compelling intervention model for similar initiatives, highlighting how overcoming cultural barriers, infrastructure limitations, and budgetary constraints through policy advocacy, strategic partnerships, and tailored approaches can significantly boost male involvement in family planning and improve reproductive health outcomes within communities.

ABSTRACTIntroduction:Since the health information system (HIS) in public health care services in Serbia was introduced in 2009, it has gradually expanded. However, it is unclear how well the HIS components have developed and the whole system’s stage of maturity.Method:In June–September 2021, a maturity assessment of the Serbian HIS was conducted for the first time using the HIS Stages of Continuous Improvement (SOCI) toolkit. The toolkit measures HIS status across 5 HIS domains: leadership and governance, management and workforce, information and communication technology (ICT), standards and interoperability, and data quality and use. The domains were further divided into 13 components and 39 subcomponents whose maturity stage was assessed on a 5-point Likert scale, indicating the level of development: (1) emerging/ad hoc; (2) repeatable; (3) defined; (4) managed; and (5) optimized. The toolkit was applied in a working group of 32 professionals and experts who were engaged in developing the new national eHealth strategy and action plan.Results:The overall maturity score of the Serbian HIS was 1.6, which indicates a low level. The highest baseline score (2) was given to the standards and interoperability domain, and the lowest (1.1) was given to ICT infrastructure. The remaining 3 domains (leadership and governance, Management and Workforce, and Data Quality and Use) were similarly rated (1.7, 1.7, and 1.6, respectively).Conclusion:A baseline assessment of the maturity level of Serbian HIS indicates that the majority of components are between the emerging/ad hoc stage and repeatable, which represent isolated, ad hoc efforts, with some basic processes in place and existing and accessible policies. This exercise provided an opportunity to address identified weaknesses in the upcoming national eHealth strategy.

ABSTRACTMore than half of births among Indigenous women in Guatemala are still being attended at home by providers with no formal training. We describe the incorporation of comadronas (traditional midwives) into casas maternas (birthing centers) in the rural highlands of western Guatemala. Although there was initial resistance to the casa, comadronas and clients have become increasingly enthusiastic about them. The casas provide the opportunity for comadronas to continue the cultural traditions of prayers, massages, and other practices that honor the vital spiritual dimension of childbirth close to home in a home-like environment with extended family support while at the same time providing a safer childbirth experience in which complications can be detected by trained personnel at the casa, managed locally, or promptly referred to a higher-level facility. Given the growing acceptance of this innovation in an environment in which geographical, financial, and cultural barriers to deliveries at higher-level facilities lead most women to deliver at home, casas maternas represent a feasible option for reducing the high level of maternal mortality in Guatemala.This article provides an update on the growing utilization of casas and provides new insights into the role of comadronas as birthing team members and enthusiastic promotors of casas maternas as a preferable alternative to home births. Through the end of 2023, these casas maternas had cared for 4,322 women giving birth. No maternal deaths occurred at a casa, but 4 died after referral.The Ministry of Health of Guatemala has recently adopted this approach and has begun to implement it in other rural areas where home births still predominate. This approach deserves consideration as a viable and feasible option for reducing maternal mortality throughout the world where home births are still common, while at the same time providing women with respectful and culturally appropriate care.

ABSTRACTTraining health workers is one of the biggest challenges and cost drivers when introducing a new contraceptive method or service delivery innovation. PATH developed a digital training curriculum for family planning providers who are learning to offer subcutaneous DMPA (DMPA-SC), including through self-injection, as an option among a range of contraceptive methods. The DMPA-SC eLearning course for health workers includes 10 lessons with an emphasis on informed choice counseling and training clients to self-inject. In partnership with Ministries of Health in Senegal and Uganda, the course was rolled out in select areas in 2019–2020, including during the COVID-19 pandemic when physical distancing requirements restricted in-person training. We conducted evaluations in both countries to assess the practical application of this digital training approach for contraceptive introduction. The evaluation consisted of a post-training survey, an observational assessment conducted during post-training supportive supervision, and an estimation of training costs.In both countries, a majority (88.6% in Uganda and 64.3% in Senegal) scored above 80% on a DMPA-SC knowledge test following the training. In Senegal, where there was a comparison group of providers trained in person, those providers scored similar on the post-test to eLearners. Providers in both groups and in both countries felt more prepared to administer DMPA-SC or offer self-injection to clients after receiving a supervision visit (93%–98% of eLearners felt very prepared after supervision as compared to 45%–72% prior). The evaluation results suggest that digital approaches offer a number of benefits, can be cost-effective, and are most optimal when blended with in-person training and/or supportive supervision.

ABSTRACTIntroduction: Nigeria has the highest number of children who have not received any vaccines in Africa. The training-of-trainers (TOT) model used to train program managers (PMs) and health care workers (HCWs) is ineffective for adult learning and limits immunization programs’ success. We incorporated adult learning principles (ALPs) in designing and delivering TOT for immunization PMs and HCWs to use data to engage communities for tailored immunization strategies.Methods: Our study was implemented in 3 local government areas (LGAs) of the Federal Capital Territory, Nigeria. A training curriculum was developed, integrating ALPs and technical and operational content based on best practices in delivering immunization training and the training needs assessment findings. State PMs (n=10), LGA PMs (n=30), and HCWs (n=42) were trained on the human-centered design for tailoring immunization programs (HCD-TIP) approaches using ALPs. We used interviews and surveys with purposively and conveniently sampled PMs and HCWs, respectively, and observations to assess participants’ satisfaction, knowledge and competence, behavior changes, and results. The interviews were analyzed thematically, and surveys were statistically.Results: There was a high level of satisfaction with the training among LGA PMs (100%), state PMs (91%), and HCWs (85%), with significant knowledge and competence improvements post-training (P<.001). The trained participants conducted 2 HCD sessions with 24 undervaccinated communities and co-designed 24 prototype solutions for testing. Results showed increased coverage of the pentavalent vaccine first dose (54%) and third dose (188%) across 12 participating communities. Improved community colaboration, communication skills, and data-driven approaches were the most cited behavior changes in practice.Conclusion: The application of ALPs in training, use of HCD-TIP approaches and tools, and supportive supervision enhanced PMs’ and HCWs’ capacity for tailored interventions. Countries should consider adopting a holistic approach that focuses on using these approaches in immunization programs to strengthen the health system for equitable vaccine coverage.

Although acute inflammation serves essential functions in maintaining tissue homeostasis, chronic inflammation is causally linked to many diseases. Macrophages are a major cell type that orchestrates inflammatory processes. During inflammation, macrophages undergo polarization and activation, thereby mobilizing pro-inflammatory and anti-inflammatory transcriptional programs that regulate ensuing macrophage functions. Fatty acid binding protein 5 (FABP5) is a lipid chaperone highly expressed in macrophages. FABP5 deletion is implicated in driving macrophages toward an anti-inflammatory phenotype, yet signaling pathways regulated by macrophage-FABP5 have not been systematically profiled. We leveraged proteomic and phosphoproteomic approaches to characterize pathways modulated by FABP5 in M1 and M2 polarized bone marrow-derived macrophages (BMDMs). Stable isotope labeling by amino acids-based analysis of M1 and M2 polarized wild-type and FABP5 knockout BMDMs revealed numerous differentially regulated proteins and phosphoproteins. FABP5 deletion impacted downstream pathways associated with inflammation, cytokine production, oxidative stress, and kinase activity. Toll-like receptor 2 (TLR2) emerged as a novel target of FABP5 and pharmacological FABP5 inhibition blunted TLR2-mediated activation of downstream pathways, ascribing a novel role for FABP5 in TLR2 signaling. This study represents a comprehensive characterization of the impact of FABP5 deletion on the proteomic and phosphoproteomic landscape of M1 and M2 polarized BMDMs. Loss of FABP5 altered pathways implicated in inflammatory responses, macrophage function, and TLR2 signaling. This work provides a foundation for future studies seeking to investigate the therapeutic potential of FABP5 inhibition in pathophysiological states resulting from dysregulated inflammatory signaling.

In nuclear medicine, estimating the number of radioactive decays that occur in a source organ per unit administered activity of a radiopharmaceutical (i.e., the time-integrated activity coefficient [TIAC]) is an essential task within the internal dosimetry workflow. TIAC estimation is commonly derived by least-squares fitting of various exponential models to organ time–activity data (radiopharmaceutical biodistribution). Rarely, however, are methods used to objectively determine the model that best characterizes the data. Additionally, the uncertainty associated with the resultant TIAC is generally not evaluated. As part of the MIRDsoft initiative, MIRDfit has been developed to offer a biodistribution fitting software solution that provides the following essential features and advantages for internal dose assessment: nuclear medicine–appropriate fit functions; objective metrics for guiding best-fit selection; TIAC uncertainty calculation; quality control and data archiving; integration with MIRDcalc software for dose calculation; and a user-friendly Excel-based interface. For demonstration and comparative validation of MIRDfit’s performance, TIACs were derived from serial imaging studies involving ¹⁸F-FDG and ¹⁷⁷Lu-DOTATATE using MIRDfit. These TIACs were then compared with TIAC estimates obtained using other software. In most cases, the TIACs agreed within approximately 10% between MIRDfit and the other software. MIRDfit has been endorsed by the MIRD Committee of the Society of Nuclear Medicine and Molecular Imaging and has been integrated into the MIRDsoft suite of free dosimetry software; it is available for download at no user cost (https://mirdsoft.org/).

Simplified methods of acquisition and quantification would facilitate the use of synaptic density imaging in multicenter and longitudinal studies of Alzheimer disease (AD). We validated a simplified tissue-to-reference ratio method using SUV ratios (SUVRs) for estimating synaptic density with [¹¹C]UCB-J PET. Methods: Participants included 31 older adults with AD and 16 with normal cognition. The distribution volume ratio (DVR) using simplified reference tissue model 2 was compared with SUVR at short scan windows using a whole-cerebellum reference region. Results: Synaptic density was reduced in AD participants using DVR or SUVR. SUVR using later scan windows (60–90 or 70–90 min) was minimally biased, with the strongest correlation with DVR. Effect sizes using SUVR at these late time windows were minimally reduced compared with effect sizes with DVR. Conclusion: A simplified tissue-to-reference method may be useful for multicenter and longitudinal studies seeking to measure synaptic density in AD.

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.

[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.

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.

BACKGROUND AND PURPOSE:

World Health Organization (WHO) grade 2 and 3 diffuse gliomas account for approximately 5% of primary brain tumors. They are invasive and infiltrative tumors and have considerable morbidity, causing progressive neurologic deterioration. The mean survival time is <10 years from diagnosis. Surgical debulking represents first-line management. The extent of resection is associated with progression-free and overall survival. Radiologic assessment of the extent of resection is challenging. This can be underestimated on early postoperative MRI, meaning that accurate assessment may be achieved only on delayed follow-up imaging. We hypothesized that DWI may help facilitate more reliable estimates of the extent of resection on early postoperative MRI. This study aimed to assess the utility of DWI in early postoperative MRI to evaluate the extent of resection.

BACKGROUND AND PURPOSE:

Previous studies have reported metal accumulation and microstructure changes in deep gray nuclei (DGN) in Wilson disease (WD). However, there are limited studies that investigate whether there is metal accumulation and microstructure changes in DGN of patients with WD with normal-appearing routine MRI. This study aimed to evaluate multiparametric changes in DGN of WD and whether the findings correlate with clinical severity in patients with WD.

BACKGROUND AND PURPOSE:

Angioplasty and stent placement have been described as a bailout technique in individuals with failed thrombectomy. We aimed to investigate Stent retriever AssIsted Lysis (SAIL) with tirofiban before angioplasty and stent placement.

BACKGROUND AND PURPOSE:

Prediction of aneurysm instability is crucial to guide treatment decisions and to select appropriate patients with unruptured intracranial aneurysms (IAs) for preventive treatment. High-resolution 4D MR flow imaging and 3D quantification of aneurysm morphology could offer insights and new imaging markers for aneurysm instability. In this cross-sectional study, we aim to identify 4D MR flow imaging markers for aneurysm instability by relating hemodynamics in the aneurysm sac to 3D morphologic proxy parameters for aneurysm instability.

BACKGROUND AND PURPOSE:

Intracranial vessel wall imaging is technically challenging to implement, given the simultaneous requirements of high spatial resolution, excellent blood and CSF signal suppression, and clinically acceptable gradient times. Herein, we present our preliminary findings on the evaluation of a deep learning–optimized sequence using T1-weighted imaging.

We present a unique case of a single patient presenting with two mutationally distinct, PD-L1⁺ diffuse large B-cell lymphomas (DLBCLs). One of these DLBCLs demonstrated exceptionally high mutational burden (eight disease-associated variants and 41 variants of undetermined significance) with microsatellite instability (MSI) and an acquired PMS2 mutation with loss of PMS2 protein expression, detected postchemotherapy. This report, while highlighting the extent of possible tumor heterogeneity across separate clonal expansions as well as possible syndromic B-cell neoplasia, supports the notion that, although rare, PD-L1 expression and associated states permissive of high mutational burden (such as mismatch repair gene loss of function/MSI) should be more routinely considered in DLBCLs. Appropriate testing may be predictive of outcome and inform the utility of targeted therapy in these genetically diverse and historically treatment-refractory malignancies.

The diagnosis of maturity-onset diabetes of the young (MODY), a monogenic form of diabetes mellitus caused by a mutation in a single gene, is often uncertain until genetic testing is performed. We report a 13-yr-old Korean boy who was initially diagnosed with type 2 diabetes (T2DM). MODY was suspected because of his nonobese body habitus and family history of multiple affected members. Targeted panel sequencing of all MODY-related genes was performed using the NextSeq 550Dx platform (Illumina). Sanger sequencing was performed using blood samples from the parents, siblings, and other relatives. A frameshift variant in the 3' region of the last exon of PDX1 was detected in the patient and his family members with diabetes. PP1_Moderate criterion was applied and this variant was confirmed to be the genetic cause of diabetes in the family and classified as likely pathogenic. The study highlights the importance of genetic testing for nonobese, early-onset diabetic patients with multiple affected family members. Increased awareness and aggressive genetic testing for MODY are needed.

TP53 plays a critical role as a tumor suppressor by controlling cell cycle progression, DNA repair, and apoptosis. Post-translational modifications such as acetylation of specific lysine residues in the DNA binding and carboxy-terminus regulatory domains modulate its tumor suppressor activities. In this study, we addressed the functional consequences of the germline TP53 p.K164E (NM_000546.5: c.490A>G) variant identified in a patient with early-onset breast cancer and a significant family history of cancer. K164 is a conserved residue located in the L2 loop of the p53 DNA binding domain that is post-translationally modified by acetylation. In silico, in vitro, and in vivo analyses demonstrated that the glutamate substitution at K164 marginally destabilizes the p53 protein structure but significantly impairs sequence-specific DNA binding, transactivation, and tumor cell growth inhibition. Although p.K164E is currently considered a variant of unknown significance by different clinical genetic testing laboratories, the clinical and laboratory-based findings presented here provide strong evidence to reclassify TP53 p.K164E as a likely pathogenic variant.