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1.
Clin Toxicol (Phila) ; : 1-6, 2024 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-39222325

RESUMO

INTRODUCTION: The use of the osmol gap as a surrogate marker of toxic alcohol poisoning is common. Unfortunately, many patients with alcoholic ketoacidosis have elevated osmol gaps and are misdiagnosed with toxic alcohol poisoning. We aimed to characterize the range of osmol gaps in patients with alcoholic ketoacidosis. METHODS: This was a retrospective poison center study. Data from 24 years were reviewed using the following case definition of alcoholic ketoacidosis: (1) documented alcohol use disorder; (2) presence of urine or serum ketones or an elevated blood beta-hydroxybutyrate concentration; (3) an anion gap ≥14 mmol/L. Potential cases of alcoholic ketoacidosis that failed to fulfill all three criteria were adjudicated by three toxicologists. Exclusion criteria included (1) detectable toxic alcohol concentration, (2) hemodialysis and/or multiple doses of fomepizole, (3) no osmol gap documented, (4) other diagnoses that lead to a metabolic acidosis. Demographics, pH, anion gap, lactate concentration, and osmol gap were extracted. RESULTS: Of 1,493 patients screened, 55 met criteria for alcoholic ketoacidosis. Sixty-four percent were male, and their median age was 52 years. The median osmol gap was 27 [IQR 18-36]. The largest anion gap was 57 mmol/L, and the lowest pH was 6.8. Forty-five (82%) of the patients with alcoholic ketoacidosis had osmol gaps >10; 38 (69%) had osmol gaps >20; 24 (44%) had osmol gaps >30; 11 (20%) had osmol gaps > 40. DISCUSSION: The large range of osmol gaps in patients with alcoholic ketoacidosis often reaches values associated with toxic alcohol poisoning. The study is limited by the potential for transcribing errors and the inability to identify the cause of the osmol gap. CONCLUSIONS: In this retrospective study, patients with alcoholic ketoacidosis had a median osmol gap of 26. Given that alcoholic ketoacidosis is easily and inexpensively treated, proper identification may prevent costly and invasive treatment directed at toxic alcohol poisoning.

2.
JOR Spine ; 7(3): e70000, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39234532

RESUMO

Background: Magnetic resonance imaging (MRI) noninvasively quantifies disc structure but requires segmentation that is both time intensive and susceptible to human error. Recent advances in neural networks can improve on manual segmentation. The aim of this study was to establish a method for automatic slice-wise segmentation of 3D disc volumes from subjects with a wide range of age and degrees of disc degeneration. A U-Net convolutional neural network was trained to segment 3D T1-weighted spine MRI. Methods: Lumbar spine MRIs were acquired from 43 subjects (23-83 years old) and manually segmented. A U-Net architecture was trained using the TensorFlow framework. Two rounds of model tuning were performed. The performance of the model was measured using a validation set that did not cross over from the training set. The model version with the best Dice similarity coefficient (DSC) was selected in each tuning round. After model development was complete and a final U-Net model was selected, performance of this model was compared between disc levels and degeneration grades. Results: Performance of the final model was equivalent to manual segmentation, with a mean DSC = 0.935 ± 0.014 for degeneration grades I-IV. Neither the manual segmentation nor the U-Net model performed as well for grade V disc segmentation. Compared with the baseline model at the beginning of round 1, the best model had fewer filters/parameters (75%), was trained using only slices with at least one disc-labeled pixel, applied contrast stretching to its input images, and used a greater dropout rate. Conclusion: This study successfully trained a U-Net model for automatic slice-wise segmentation of 3D disc volumes from populations with a wide range of ages and disc degeneration. The final trained model is available to support scientific use.

3.
Aging Cell ; : e14295, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39102872

RESUMO

Senescence is an important cellular program occurring in development, tissue repair, cancer, and aging. Increased senescence is also associated with disease states, including obesity and Type 2 diabetes (T2D). Characterizing and quantifying senescent cells at a single cell level has been challenging and particularly difficult in large primary cells, such as human adipocytes. In this study, we present a novel approach that utilizes reflected light for accurate senescence-associated beta-galactosidase (SABG) staining measurements, which can be integrated with immunofluorescence and is compatible with primary mature adipocytes from both human and mouse, as well as with differentiated 3T3-L1 cells. This technique provides a more comprehensive classification of a cell's senescent state by incorporating multiple criteria, including robust sample-specific pH controls. By leveraging the precision of confocal microscopy to detect X-gal crystals using reflected light, we achieved superior sensitivity over traditional brightfield techniques. This strategy allows for the capture of all X-gal precipitates in SABG-stained samples, revealing diverse X-gal staining patterns and improved detection sensitivity. Additionally, we demonstrate that reflected light outperforms western blot analysis for the detection and quantification of senescence in mature human adipocytes, as it offers a more accurate representation of SABG activity. This detection strategy enables a more thorough investigation of senescent cell characteristics and specifically a deeper look at the relationship between adipocyte senescence and obesity associated disorders, such as T2D.

4.
J Urol ; : 101097JU0000000000004147, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-39093847

RESUMO

PURPOSE: Multiple factors are thought to give rise to common, recurrent kidney stone disease, but for monogenic stone disorders a firm diagnosis is possible through genetic testing. The autosomal recessive primary hyperoxalurias (PH) are rare forms of monogenic kidney stone disease. All 3 types of PH are caused by inborn errors of glyoxylate metabolism in the liver, leading to hepatic oxalate overproduction and excessive renal urinary oxalate excretion. These conditions are characterized by kidney stones, nephrocalcinosis, progressive chronic kidney disease, and kidney failure. Systemic oxalosis, the extra-renal deposition of oxalate resulting in severe morbidity and mortality, occurs in chronic kidney disease when oxalate clearance by the kidneys declines. Novel small interfering RNA-based therapeutics targeting the liver to reduce urinary oxalate excretion have been approved, introducing precision medicine to treat primary hyperoxaluria type 1. The goal of this narrative review is to address the benefits and practicalities of genetic testing for suspected monogenic kidney stone disease and the critical roles of a multidisciplinary team. MATERIALS AND METHODS: We collated our procedures, education, training, and workflows to help other clinicians integrate genetic assessment into their diagnostic routines. RESULTS: In our experience, increased access to genetic testing facilitates early detection of PH and other monogenic causes of kidney stone disease so that individualized care can be instituted promptly. CONCLUSIONS: Alongside biochemical assessments, more widespread genetic testing may ensure more timely diagnoses so that patients with suspected monogenic kidney stone disease gain access to an expanded range of services and enrollment in clinical trials and registries.

5.
J Vet Intern Med ; 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39175162

RESUMO

BACKGROUND: Human patients with Ehlers-Danlos syndrome (EDS) are categorized into subtypes based on causative genetic variants and phenotypes. The classical form of EDS, primarily caused by variants in COL5A1 or COL5A2, is a very common subtype in people but is poorly characterized in dogs. OBJECTIVE: Describe likely causal COL5A1 variants in dogs with classical EDS, summarize clinical histories, discuss potential disease mechanisms, and draw conclusions about disease prognosis. ANIMALS: Seven client-owned dogs that exhibited clinical signs of classical EDS. METHODS: Clinical information was recorded from medical records and communication with attending veterinarians and dog owners. To identify potential causal gene sequence variants whole-genome sequence analyses (n = 6) or Sanger sequencing (n = 1) were performed on DNA isolated from the probands. Pathological abnormalities in skin biopsy samples were assessed using histology and electron microscopy in 3 dogs. RESULTS: Six distinct heterozygous COL5A1 sequence variants were identified. The most common clinical signs included fragile skin (n = 7), hyperextensible skin (n = 7), joint hypermobility (n = 6), and atrophic scars (n = 5). The median age at last follow-up or death was 12 years (range, 6.5-14 years). Ultrastructural abnormalities in dermal collagen differed among dogs with different COL5A1 variants. CONCLUSION AND CLINICAL IMPORTANCE: We describe the genotypic and phenotypic spectrum of the classical subtype of EDS by identifying 6 novel COL5A1 variants in conjunction with detailed clinical histories that included long-term follow-up information in 7 dogs.

6.
Sci Total Environ ; : 175067, 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39111421

RESUMO

Phytoplanktonic overgrowth, which characterizes the eutrophication or trophic status of surface water bodies, threatens ecosystems and public health. Quantitative polymerase chain reaction (qPCR) is promising for assessing the abundance and community composition of phytoplankton. However, applications of qPCR to indicate eutrophication and trophic status, especially in lotic systems, have yet to be comprehensively evaluated. For the first time, this study correlates qPCR-based phytoplankton abundance with chlorophyll a (the most widely used indicator of eutrophication and trophic status) in multiple freshwater rivers. From early summer to late fall in 2017, 2018, and 2019, we evaluated phytoplankton, chlorophyll a, pheophytin a, and the Trophic Level Index (TLI) in twelve large freshwater rivers in three regions (western, midcontinent, and eastern) in the United States. Chlorophyll a concentration had positive allometric correlations with qPCR-based phytoplankton abundance (adjusted R2 = 0.5437, p-value <0.001), pheophytin a concentration (adjusted R2 = 0.3378, p-value <0.001), and TLI (adjusted R2 = 0.4789, p-value <0.001). Thus, a greater phytoplankton abundance suggests a higher trophic status. This work also presents the numerical values of qPCR-based phytoplankton abundance defining the boundaries among trophic statuses (e.g., oligotrophic, mesotrophic, and eutrophic) of freshwater rivers. The sampling sites in the midcontinent rivers were more eutrophic because they had significantly higher chlorophyll a concentrations, pheophytin a concentrations, and TLI values than in the western and eastern rivers. The higher phytoplankton abundance at the midcontinent sites confirmed their higher trophic status. By linking qPCR-based phytoplankton abundance to chlorophyll a, this study demonstrates that qPCR is a promising avenue to investigate the population dynamics of phytoplankton and the trophic status (or eutrophication) of freshwater rivers.

7.
Artigo em Inglês | MEDLINE | ID: mdl-39158462

RESUMO

BACKGROUND: Various population-based studies have shown Hispanic/Latino ethnicity is a risk factor for worse survival in patients with gastric cancer linked to disparate access to care. We aimed to address whether Hispanic patients treated within safety-net hospital systems continue to experience this survival deficit compared to non-Hispanic patients. METHODS: We performed a retrospective cohort study comparing survival between Hispanic and non-Hispanic patients diagnosed with gastric adenocarcinoma between January 1, 2016 to December 31, 2020 within Los Angeles County's safety-net hospital system. Gastric cancer-specific survival was compared between the two cohorts using the Kaplan-Meier estimate and Cox proportional-hazards regression model. RESULTS: 448 patients who received care from five medical centers were included. 348 (77.7%) patients self-identified as Hispanic and 100 (22.3%) as non-Hispanic. Mean follow-up time was 2.0 years (median 0.91 years, IQR, 0.34-2.5 years). Hispanic patients were found to be diagnosed at a younger age (55.6 vs 60.7 years, p <0.01), demonstrate higher state area deprivation index (6.4 vs 5.0, p <0.01), and present with metastatic disease (59.8% vs 45%, p =0.04). After adjusting social and oncologic variables, Hispanic ethnicity remained an independent risk factor for worse survival (HR 1.56, [95% CI 1.06-2.28], p = 0.02). CONCLUSIONS: Hispanic patients treated within a large, multi-center safety-net hospital system experience worse survival compared to non-Hispanic patients. This suggests ethnic disparities exist within safety-net hospital systems, independent of known clinicopathologic factors. IMPACT: Improving outcomes for Hispanic patients with gastric cancer requires future efforts aimed at defining and addressing these unidentified barriers to care.

8.
Geohealth ; 8(8): e2023GH001005, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39165476

RESUMO

The incidence of vibriosis is rising globally with evidence of climate variability influencing environmental processes that support growth of pathogenic Vibrio spp. The waterborne pathogen, Vibrio vulnificus can invade wounds and has one of the highest case fatality rates in humans. The bacterium cannot be eradicated from the aquatic environment, hence climate driven environmental conditions enhancing growth and dissemination of V. vulnificus need to be understood to provide preemptive assessment of its presence and distribution in aquatic systems. To achieve this objective, satellite remote sensing was employed to quantify the association of sea surface temperature (SST) and chlorophyll-a (chl-a) in locations with reported V. vulnificus infections. Monthly analysis was done in two populated regions of the Gulf of Mexico-Tampa Bay, Florida, and Galveston Bay, Texas. Results indicate warm water, characterized by a 2-month lag in SST, high concentration of phytoplankton, proxied for zooplankton using 1 month lagged chl-a values, was statistically linked to higher odds of V. vulnificus infection in the human population. Identification of climate and ecological processes thresholds is concluded to be useful for development of an heuristic prediction system designed to determine risk of infection for coastal populations.

9.
Proc Natl Acad Sci U S A ; 121(34): e2319724121, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39141348

RESUMO

Skeletal muscle atrophy is a morbidity and mortality risk factor that happens with disuse, chronic disease, and aging. The tissue remodeling that happens during recovery from atrophy or injury involves changes in different cell types such as muscle fibers, and satellite and immune cells. Here, we show that the previously uncharacterized gene and protein Zfp697 is a damage-induced regulator of muscle remodeling. Zfp697/ZNF697 expression is transiently elevated during recovery from muscle atrophy or injury in mice and humans. Sustained Zfp697 expression in mouse muscle leads to a gene expression signature of chemokine secretion, immune cell recruitment, and extracellular matrix remodeling. Notably, although Zfp697 is expressed in several cell types in skeletal muscle, myofiber-specific Zfp697 genetic ablation in mice is sufficient to hinder the inflammatory and regenerative response to muscle injury, compromising functional recovery. We show that Zfp697 is an essential mediator of the interferon gamma response in muscle cells and that it functions primarily as an RNA-interacting protein, with a very high number of miRNA targets. This work identifies Zfp697 as an integrator of cell-cell communication necessary for tissue remodeling and regeneration.


Assuntos
Músculo Esquelético , Proteínas de Ligação a RNA , Animais , Camundongos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Humanos , Inflamação/metabolismo , Inflamação/patologia , Inflamação/genética , Camundongos Knockout , Atrofia Muscular/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/patologia , MicroRNAs/genética , MicroRNAs/metabolismo , Camundongos Endogâmicos C57BL , Interferon gama/metabolismo
10.
Am J Obstet Gynecol ; 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39111516

RESUMO

OBJECTIVE: Financial strain and unmet social needs are associated with greater risk for lower urinary tract symptoms. Little research has examined financial strain and unmet social needs in relation to the more holistic concept of bladder health. This study utilizes baseline data from RISE FOR HEALTH: A U.S. Study of Bladder Health to examine whether financial strain, unmet social needs, and meeting specific federal poverty level threshold levels are associated with lower urinary tract symptoms and poorer perceived bladder health, well-being, and function. STUDY DESIGN: Participants were 18 years or older, born female or currently identified as a woman, and from the civilian, noninstitutionalized population residing in 50 counties in the United States that included or surrounded 9 recruitment centers. Data were collected through mailed or internet-based surveys. To address research questions, the 10-item Lower Urinary Tract Dysfunction Research Network - Symptom Index and selected Prevention of Lower Urinary Tract Symptoms Research Consortium bladder health scores were separately regressed on each financial strain, unmet social need, and federal poverty level variable, using linear regression adjusting for covariates (age, race/ethnicity, education, and vaginal parity) and robust variance estimation for confidence intervals (CI). Participants with no missing data for a given analysis were included (range of n=2564-3170). In separate sensitivity analyses, body mass index, hypertension, and diabetes were added as covariates and missing data were imputed. RESULTS: The mean age of participants was 51.5 years (standard deviation=18.4). Not having enough money to make ends meet, housing insecurity, food insecurity, unreliable transportation, and percent federal poverty levels of 300% or less were consistently associated with more reported lower urinary tract symptoms and poorer perceived bladder health. For example, compared to food secure participants, women who worried that their food would run out at the end of the month had a Lower Urinary Tract Dysfunction Research Network - Symptom Index score that was 3.4 points higher (95% CI: 2.5, 4.3), on average. They also had lower mean scores across different bladder health measures, each assessed using a 100-point scale: global bladder health (-8.2, 95% CI: -10.8, -5.7), frequency (-10.2, 95% CI: -13.8, -6.7), sensation (-11.6, 95% CI: -15.1, -8.2), continence (-13.3, 95% CI: -16.7, -9.9), and emotional impact of bladder health status (-13.2, 95% CI: -16.5, -9.9). Across analyses, associations largely remained significant after additional adjustment for body mass index, hypertension, and diabetes. The pattern of results when imputing missing data was similar to that observed with complete case analysis; all significant associations remained significant with imputation. CONCLUSION: Financial strain and unmet social needs are associated with worse LUTS and poorer bladder health. Longitudinal research is needed to examine whether financial strain and unmet social needs influence the development, maintenance, and worsening of lower urinary tract symptoms; different mechanisms by which financial strain and unmet social needs may impact symptoms; and the degree to which symptoms contribute to financial strain. If supported by etiologic research, prevention research can be implemented to determine whether the amelioration of financial strain and social needs, including enhanced access to preventative care, may promote bladder health across the life course.

11.
BMJ Case Rep ; 17(8)2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39117364

RESUMO

A 22-kg female in early childhood with a history of reactive airway disease presented to a paediatric emergency department with acute shortness of breath, tachypnoea and wheezing. Despite treatment with albuterol and corticosteroids, her bronchospasm persisted, prompting the administration of terbutaline. The patient received 220 mcg (10 mcg/kg) terbutaline intravenously, followed immediately by an inadvertent supratherapeutic intravenous dose of 10 000 mcg (454.5 mcg/kg). The patient's laboratory results obtained minutes after the medication error were notable for: potassium, 3.1 mmol/L, lactate, 2.6 mmol/L and troponin I, 0.30 ng/mL (normal <0.03 ng/mL). Over the next 48 hours, serial serum troponin values decreased. The patient was discharged home approximately 72 hours after the initial presentation and she remained well based on follow-up calls over the next several months. Given the timing and trend of troponin concentrations, we do not believe the terbutaline overdose to be responsible for the myocardial injury.


Assuntos
Overdose de Drogas , Terbutalina , Humanos , Terbutalina/administração & dosagem , Feminino , Broncodilatadores/administração & dosagem , Administração Intravenosa , Troponina I/sangue , Pré-Escolar
12.
JACC Adv ; 3(7): 100995, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39129999

RESUMO

Background: Traditionally, low cardiac output has been considered the primary hemodynamic driver of renal function and injury. Adult data suggest that central venous pressure (CVP) is a more important factor. Objectives: The authors hypothesized that in children with cardiovascular disease, higher CVP predicts lower estimated glomerular filtration rate (eGFR) and worsening renal function (WRF). Methods: We performed a single-center cohort study of patients aged 3 months to 21 years with biventricular circulation undergoing cardiac catheterization. Pearson's correlation and linear and Cox regression analyses were performed to determine associations with eGFR at the time of catheterization and WFR within 180 days after catheterization. Results: 312 patients had median age 7.9 years (IQR: 2.3 to 14.5 years), median eGFR 97 mL/min/1.73 m2 (IQR: 81-118 mL/min/1.73 m2), median CVP 7 mm Hg (IQR: 5-9 mm Hg), and median cardiac index 3.7 mL/min/m2 (IQR: 2.9-4.6 mL/min/m2). Nearly half (48%) were transplant recipients. In multivariable analysis, CVP was independently associated with eGFR (ß = -2.65; 95% CI: -4.02, -1.28; P < 0.001), as was being a transplant recipient (ß = -10.20; 95% CI: -17.74, -2.65; P = 0.008), while cardiac index was not. Fifty-one patients (16%) developed WRF. In a proportional hazards model adjusting for cardiac index, only higher CVP (HR: 1.10; 95% CI: 1.04-1.17; P = 0.002) and greater contrast volume by weight (HR: 1.05; 95% CI: 1.01-1.10; P = 0.021) predicted WRF. CVP ≥7 mm Hg likewise predicted WRF (HR: 2.57; 95% CI: 1.29-5.12; P = 0.007). Conclusions: Among children with a spectrum of cardiovascular disease, higher CVP is associated with lower eGFR and development of WRF, independent of cardiac index.

13.
Biochem Biophys Rep ; 39: 101765, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39040543

RESUMO

Primary Hyperoxaluria Type 3 (PH3) results from 4-hydroxy-2-oxoglutarate (HOG) aldolase (HOGA) deficiency, which causes an increase in endogenous oxalate synthesis leading to calcium oxalate kidney stone disease. The mechanisms underlying HOG metabolism and increased oxalate synthesis in PH3 are not well understood. We used a Hoga1 knock-out mouse model of PH3 to investigate two aspects of HOG metabolism: reduction to dihydroxyglutarate (DHG), a pathway that may limit oxalate synthesis in PH3, and metabolism to glyoxylate, which is a direct precursor to oxalate. The metabolism of HOG to DHG was highest in liver and kidney cortical tissue, enhanced in the cytosolic compartment of the liver, and preferred NADPH as a cofactor. In the absence of HOGA, HOG to glyoxylate aldolase activity was highest in liver mitoplasts, with no activity present in brain tissue lysates. These findings will assist in the identification of enzymes responsible for the metabolism of HOG to DHG and glyoxylate, which may lead to novel therapeutic approaches to limit oxalate synthesis in those afflicted with PH3.

14.
Rev Sci Instrum ; 95(7)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-39037303

RESUMO

There are few techniques available for chemists to obtain time-to-explosion data with known temperature inputs at the early stages of the design and synthesis of new explosives. In the 1960s, a technique was developed to rapidly heat milligram-quantities of confined explosives to ∼1000 K on microsecond timescales. Wenograd [Trans. Faraday Soc. 57, 1612 (1961)] loaded explosives inside stainless steel hypodermic needles, connected them to a fireset and rapidly discharged a capacitor through the steel. He obtained the temperature by measuring the needle resistance in a Wheatstone bridge arrangement and the time to explosion from a needle rupture. However, owing to the narrow-gauge needles used in the original research, the experiment was only possible with melt-castable explosives; it was never replicated, and modern diagnostics are now available with advances beyond the 1960s. Here, we report the development of the High Explosives Initiation Time (HEIT) test, which utilizes a 250 J pulsed power system to heat the needles. This work extends the Wenograd approach by using optical diagnostics, computational modeling, and advanced techniques to measure needle resistance and needle rupture. Preliminary rate information for pentaerythritol tetranitrate (PETN) will be presented.

15.
Artigo em Inglês | MEDLINE | ID: mdl-38981690

RESUMO

Intramedullary nails are specialized metal rods inserted into the medullary cavity of a fractured bone and secured to reduce load on the fracture site, provide stability, and permit healing. The purpose of this review is to highlight the biomechanics of orthopaedic intramedullary nailing, as well as discuss the biomechanical considerations that have shaped implant design and fixation technique in veterinary and human medicine. Relevant studies were included from the PubMed database and Google Scholar for discussion on the basic science and nail design of intramedullary nails. Implant design and implementation continues to progress, with new innovative designs currently under investigation. A lack of consensus remains on the superior implant material. Recent studies, particularly in human populations, have supported the use of reaming based on reoperation rates, nonunion rates, and dynamization. Design modifications, such as the expandable intramedullary nails and angle-stable interlocking designs, have been investigated as methods of improving cortical contact and resisting torsional stress. Intramedullary nailing is a valuable stabilization technique for long bone fractures across a variety of species. The technology continues to undergo design improvements in both veterinary and human medicine.

16.
ACS Omega ; 9(29): 32097-32106, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-39072092

RESUMO

Pentaerythritol tetranitrate (PETN) has been used extensively in commercial detonators and other explosive applications for many decades. Here, we show the results of a comprehensive 1.5 year aging study of PETN in commercial detonators, addressing batch-to-batch variations, surface area changes, and comparisons of aged loose powders side-by-side with identically aged detonators. Function time analysis of the aged detonators has also been provided and discussed in the context of powder aging. This large-scale, statistically relevant study addresses long-standing questions on PETN aging without the complications from making comparisons between multiple batches of material. We have evaluated the aging time required to reach the maximum measured amount of PETN coarsening and estimated an activation barrier of ∼123 kJ mol-1, which is higher than literature values reported by Gee et al. It is possible that this discrepancy is due to the fact that that this study cannot quantify the relative contributions of surface diffusion versus sublimation processes. At the lower temperatures of 50 and 60 °C, we assume that surface diffusion dominates over sublimation processes, even at longer aging times. At the higher temperature of 75 °C, we assume that both surface diffusion and sublimation contribute at the early time points, which are included in the Arrhenius analysis for coarsening.

17.
Chem Commun (Camb) ; 60(64): 8399-8402, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39028006

RESUMO

Here we report the synthesis and characterization of diiron complexes containing triaryl N4 and N2S2 ligands derived from o-phenylenediamine. The complexes display significant differences in Fe-Fe distances and magnetic properties that depend on the identity of the flanking NMe2 and SMe donor groups.

18.
Org Biomol Chem ; 22(31): 6308-6320, 2024 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-39037740

RESUMO

Amide bonds are one of the most prevalent phenomena in nature and are utilized frequently in drug and material design. However, forming amide bonds is not always efficient or high yielding, particularly when the amine used to conjugate to a carboxylic acid is a weak nucleophile. This limitation precludes many useful amino compounds from participating in conjugation reactions to form amides. A particularly valuable amino compound, which is also a very weak nucleophile, is the amino porphyrin, valued for its role as a photosensitizer, fluorescent agent, catalyst, or, upon metalation, even a very efficient contrast agent for magnetic resonance imaging (MRI). In this work, we propose fast and high-yield coupling of an unreactive amine - the amino porphyrin - to carboxylic acid via isothiocyanate conjugation. Reactions can be achieved in one step at room temperature in one hour, achieving quantitative conversion and near perfect selectivity. Both metalated and unmetalated porphyrin, as well as fluorescein isothiocyanate (FITC), demonstrated efficient conjugation. To illustrate the value of the proposed method, we created a new blood-pool MRI contrast agent that reversibly binds to serum albumin. This new blood-pool agent, known as MITC-Deox (MRI isothiocyanate that links with deoxycholic acid), substantially reduced T1 relaxation times in blood vessels in mice, remained stable for 1 hour, cleared from blood by 24 hours, and was eliminated from the body after 4 days. The proposed method for efficient amide formation is a superior alternative to existing coupling methods, opening a door to novel synthesis of MRI contrast agents and beyond.


Assuntos
Amidas , Meios de Contraste , Porfirinas , Porfirinas/química , Porfirinas/síntese química , Amidas/química , Amidas/síntese química , Animais , Camundongos , Meios de Contraste/química , Meios de Contraste/síntese química , Imageamento por Ressonância Magnética , Estrutura Molecular , Isotiocianatos/química , Fluoresceína-5-Isotiocianato/química
19.
Biochem J ; 481(13): 865-881, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38958472

RESUMO

Filamin A is an essential protein in the cell cytoskeleton because of its actin binding properties and unique homodimer rod-shaped structure, which organises actin into three-dimensional orthogonal networks imperative to cell motility, spreading and adhesion. Filamin A is subject to extensive posttranslational modification (PTM) which serves to co-ordinate cellular architecture and to modulate its large protein-protein interaction network which is key to the protein's role as a cellular signalling hub. Characterised PTMs include phosphorylation, irreversible cleavage, ubiquitin mediated degradation, hydroxylation and O-GlcNAcylation, with preliminary evidence of tyrosylation, carbonylation and acetylation. Each modification and its relation to filamin A function will be described here. These modifications are often aberrantly applied in a range of diseases including, but not limited to, cancer, cardiovascular disease and neurological disease and we discuss the concept of target specific PTMs with novel therapeutic modalities. In summary, our review represents a topical 'one-stop-shop' that enables understanding of filamin A function in cell homeostasis and provides insight into how a variety of modifications add an extra level of Filamin A control.


Assuntos
Filaminas , Processamento de Proteína Pós-Traducional , Filaminas/metabolismo , Humanos , Animais , Fosforilação , Neoplasias/metabolismo
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