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1.
ANZ J Surg ; 2024 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-39394756

RESUMEN

BACKGROUND: Pelvic exenteration for rectal cancer involves a radical multi-visceral resection to improve complete surgical clearance, and access is limited within Queensland. METHODS: A retrospective review of a prospective database of the referrals to the pelvic exenteration service in the Royal Brisbane and Women's Hospital from 2009 to2023. Geographic, as well as clinical and demographic information was collected. RESULTS: One hundred and seventy six patients were referred to the pelvic exenterations service. In total 93 patients were referred from a major city, 52 from inner regional areas, and 31 from outer regional or remote areas. One hundred and three referred patients (58.5%) proceeded to surgery, significantly more of whom were referred from a major city (P < 0.001). Of the patients referred from outer regional, inner regional, and major cities, a similar proportion of patients proceeded to surgery (55%, 52%, and 63.4%). Patients not proceeding to surgery in major cities and inner regional areas were most commonly unfit to proceed, whereas in outer regional areas most patients decided against surgery (61.5%). In the 14-year period, overall referrals increased, with inner regional referrals increasing the most over time. Overall survival was not significantly impacted by remoteness. CONCLUSION: Awareness of the pelvic exenteration service in regional Queensland may have resulted in less referrals to the service. It is important to confirm a broad-reaching service to optimize patient care.

2.
Antimicrob Agents Chemother ; : e0111624, 2024 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-39480073

RESUMEN

Patients undergoing elective pelvic exenteration surgery who receive piperacillin/tazobactam as surgical prophylaxis are at risk of suboptimal intraoperative antibiotic exposure. With this work, we aimed to study the plasma pharmacokinetics of piperacillin and tazobactam in this population to provide dosing recommendations that optimize antibiotic exposure. We developed a prospective, observational, pharmacokinetic study of piperacillin/tazobactam in patients undergoing pelvic exenteration. Population pharmacokinetic analysis and Monte Carlo simulations were performed with Monolix and Simulx software. Probabilities of target attainment of different dosing regimens against the minimum inhibitory concentration (MIC) breakpoints (8 and 16 mg/L) were calculated. Twelve patients were included in the study, with a median age of 50.0 years [interquartile interval (45.3-57.5)] and a median weight of 79.0 kg (61.3-88.3). Median surgical time was 10.5 h (9.8-11.7). A two-compartment linear model best fitted piperacillin and tazobactam data (190 plasma samples). Monte Carlo simulations showed that a lower dose of 2 g/0.25 g loading dose followed by 4 g/0.5 g q8h by continuous infusion provided ≥90% probability of target attainment for MIC = 16 mg/L for most of the patients. For non-continuous infusion regimens, only the 2-hourly bolus re-dosing achieved intraoperative concentrations of piperacillin ≥16 mg/L. Patients with weights ≥ 100 kg and glomerular filtration rates ≥ 120 mL/min required 4 g/0.5 g q6h by continuous infusion after a loading dose. In conclusion, continuous infusion of lower doses of piperacillin/tazobactam is as adequate as the 2-hourly re-dosing recommended by the current guidelines for surgical prophylaxis in pelvic exenteration. Patients with higher weights and glomerular filtration rates are at greater risk of inadequate exposure.

3.
Clin Nutr ESPEN ; 62: 88-94, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38901953

RESUMEN

BACKGROUND & AIMS: Pelvic exenteration (PE) surgery is now a widely accepted procedure that is increasingly being performed worldwide but has significant morbidity. Although nutrition status, body mass index (BMI) and postoperative nutrition support practices are modifiable risk factors, few studies have examined the relationship of these with clinical outcomes following PE. The aim of this study was therefore to investigate the impact of these factors on postoperative complications and length of hospital stay (LOHS) following PE. METHODS: This was a retrospective cohort study of all patients having total PE surgery at a tertiary teaching hospital from 2012 to 2021 (n = 69). Multivariable analyses were undertaken to confirm univariate associations and adjust for confounding variables. Binary logistic regression was undertaken to explore predictors of infectious and Grade III or above Clavien-Dindo complications, and negative binomial regression to identify predictors of LOHS. RESULTS: Patients who were malnourished according to the Subjective Global Assessment were 5.66 (OR 5.66, 95% CI 1.07-29.74, p = 0.041) times more likely to develop an infectious complication. Increasing BMI was independently associated with development of Grade III or above Clavien-Dindo complications (p = 0.040). For each additional day until full diet commencement, there was a 19% (OR: 1.19, 95% CI 1.05-1.34, p = 0.005) increased incidence of significant complications and a 5.6% (IRR: 1.056, 95% CI: 1.02-1.09, p = 0.002) longer LOHS on multivariable analysis. There was a high rate of prolonged postoperative ileus (78%). The implementation of a nutrition support pathway with routine postoperative parenteral nutrition (PN) resulted in patients achieving adequate nutrition 7 days faster (p < 0.001) with minimal line-related complications (1.4% line-related thrombus). Routine PN did not impact ileus rates (p = 0.33) or time to diet commencement (p = 0.6). CONCLUSIONS: Preoperative malnutrition and higher BMI were associated with complications following PE. Delay to full diet commencement was associated with increased complications and longer LOHS. Routine postoperative PN appears safe and resulted in patients achieving adequate nutrition faster.


Asunto(s)
Índice de Masa Corporal , Tiempo de Internación , Estado Nutricional , Exenteración Pélvica , Complicaciones Posoperatorias , Humanos , Femenino , Estudios Retrospectivos , Masculino , Complicaciones Posoperatorias/epidemiología , Persona de Mediana Edad , Anciano , Factores de Riesgo , Desnutrición , Adulto , Apoyo Nutricional
4.
Bioorg Med Chem Lett ; 100: 129630, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38307441

RESUMEN

A series of macrocyclic PKCθ inhibitors based on a 1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one hinge binder has been studied. Different aromatic and heteroaromatic substituents have been explored in order to optimize potency, isoform selectivity as well as DMPK properties. The importance of the length of the macrocyclic linker has also been analyzed. In particular, it has been found that methyl substitutions on the linker can have a profound influence on both potency and metabolic stability. Several compounds showing very good profiles, suitable for in vivo testing, are disclosed.

5.
Cancers (Basel) ; 15(18)2023 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-37760439

RESUMEN

INTRODUCTION: Historically, surgical resection for patients with locally recurrent rectal cancer (LRRC) had been reserved for those without metastatic disease. 'Selective' patients with limited oligometastatic disease (OMD) (involving the liver and/or lung) are now increasingly being considered for resection, with favourable five-year survival rates. METHODS: A retrospective analysis of consecutive patients undergoing multi-visceral pelvic resection of LRRC with their oligometastatic disease between 1 January 2015 and 31 August 2021 across four centres worldwide was performed. The data collected included disease characteristics, neoadjuvant therapy details, perioperative and oncological outcomes. RESULTS: Fourteen participants with a mean age of 59 years were included. There was a female preponderance (n = 9). Nine patients had liver metastases, four had lung metastases and one had both lung and liver disease. The mean number of metastatic tumours was 1.5 +/- 0.85. R0 margins were obtained in 71.4% (n = 10) and 100% (n = 14) of pelvic exenteration and oligometastatic disease surgeries, respectively. Mean lymph node yield was 11.6 +/- 6.9 nodes, with positive nodes being found in 28.6% (n = 4) of cases. A single major morbidity was reported, with no perioperative deaths. At follow-up, the median disease-free survival and overall survival were 12.3 months (IQR 4.5-17.5 months) and 25.9 months (IQR 6.2-39.7 months), respectively. CONCLUSIONS: Performing radical multi-visceral surgery for LRRC and distant oligometastatic disease appears to be feasible in appropriately selected patients that underwent good perioperative counselling.

6.
Neurotoxicol Teratol ; 99: 107286, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37442398

RESUMEN

Valproic acid (VPA) is an anti-epileptic medication that increases the risk of neural tube defect (NTD) outcomes in infants exposed during gestation. Previous studies into VPA's mechanism of action have focused on alterations in gene expression and metabolism but have failed to consider how exposure changes the abundance of critical developmental proteins over time. This study evaluates the effects of VPA on protein abundance in the developmentally distinct tissues of the mouse visceral yolk sac (VYS) and embryo proper (EMB) using mouse whole embryo culture. Embryos were exposed to 600 µM VPA at 2 h intervals over 10 h during early organogenesis with the aim of identifying protein pathways relevant to VPA's mechanism of action in failed NTC. Protein abundance was measured through tandem mass tag (TMT) labeling followed by liquid chromatography and mass spectrometry. Overall, there were over 1500 proteins with altered abundance after VPA exposure in the EMB or VYS with 428 of these proteins showing previous gene expression associations with VPA exposure. Limited overlap of significant proteins between tissues supported the conclusion of independent roles for the VYS and EMB in response to VPA. Pathway analysis of proteins with increased or decreased abundance identified multiple pathways with mechanistic relevance to NTC and embryonic development including convergent extension, Wnt Signaling/planar cell polarity, cellular migration, cellular proliferation, cell death, and cytoskeletal organization processes as targets of VPA. Clustering of co-regulated proteins to identify shared patterns of protein abundance over time highlighted 4 h and 6/10 h as periods of divergent protein abundance between control and VPA-treated samples in the VYS and EMB, respectively. Overall, this study demonstrated that VPA temporally alters protein content in critical developmental pathways in the VYS and the EMB during early organogenesis in mice.


Asunto(s)
Defectos del Tubo Neural , Ácido Valproico , Humanos , Embarazo , Femenino , Ratones , Animales , Ácido Valproico/toxicidad , Proteínas/metabolismo , Embrión de Mamíferos , Defectos del Tubo Neural/metabolismo , Organogénesis
7.
Eur J Pharm Sci ; 188: 106519, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37478583

RESUMEN

Tetralysal® is a Galderma oral drug product (DP) marketed for the treatment of acne. Tetralysal® is sold in capsules containing either 150 mg or 300 mg of the drug substance. In the British Pharmacopoeia monograph for Lymecycline Capsules, the impurities already specified in the drug substance (A-G), visible in the European Pharmacopoeia 〈1654〉, are also specified together with an unidentified impurity at RRT 1.6 (Impurity J). Based on both monographs Galderma has focused on characterizing most of specified and unspecified impurities to better understand the stability and degradation processes of the formulation. In this manuscript, through both formal synthesis, preparative LCMS and formal degradation studies, we are the first group to confirm the structural identities of 5 unidentified impurities (Impurity J (RRT 1.6), RRT 2.2, 2.4, 2.6 and 3.4), conditions which exacerbate the formation of all 5 impurities and response factors for RRT 2.2, 2.6 and 3.4.


Asunto(s)
Contaminación de Medicamentos , Limeciclina , Cromatografía Líquida de Alta Presión
8.
J Pharm Biomed Anal ; 220: 114993, 2022 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-36007309

RESUMEN

Lymecycline is the drug substance (DS) used in the Galderma drug product Tetralysal® capsules with 7 impurities currently described in the pharmacopeia labelled as A-G. In the current monograph, the structural identity of all impurities except E and F have been formally identified. In this manuscript, through both formal synthesis and preparative chromatography, we are the first group to confirm the structural identity, response factor of Impurity F and conditions which exacerbate the formation of both impurities.


Asunto(s)
Contaminación de Medicamentos , Limeciclina , Cápsulas , Cromatografía Líquida de Alta Presión/métodos , Contaminación de Medicamentos/prevención & control
10.
ANZ J Surg ; 92(4): 813-818, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34994080

RESUMEN

BACKGROUND: Anastomotic leak (AL) is the anathema of colorectal surgery. Early diagnosis is an essential segue to early intervention. A temporary diverting ileostomy (TDI) does not prevent an AL and presents inherent complications of its own. Numerous drain fluid biomarkers (BM) have been studied in colorectal surgery and extravasated intraluminal substances (EILS) such as amylase have shown promise. The aim of this study was to assess drain fluid amylase (DFA) as a BM of AL after minimally invasive rectal resection without a TDI. METHODS: A single centre prospective cohort study performed from 2018 to 2021. The primary outcome was DFA measured daily whilst the drain was in situ. Rectal tube amylase was also measured for the first two post-operative days to quantitate the intra-luminal levels of the enzyme. DFA was compared between patients who experienced AL and those who did not. RESULTS: Of the 62 patients studied, six (9.7%) experienced AL. There was a statistically significant difference in DFA between patients who experienced AL (Median:1373.5 U/L; IQR: 306-7953) and patients who did not experience an AL (Median: 27.0 U/L; IQR: 16-38); p < 0.0001. CONCLUSIONS: The measurement of drain fluid amylase is a highly sensitive BM of early clinical anastomotic leak in patients undergoing a rectal resection with an extraperitoneal anastomosis and when a TDI is not incorporated. This simple, inexpensive and non-invasive test should be considered in all patients as an adjunct to the clinical diagnosis and differentiation of AL from other postoperative complications.


Asunto(s)
Fuga Anastomótica , Neoplasias del Recto , Amilasas , Anastomosis Quirúrgica , Fuga Anastomótica/diagnóstico , Fuga Anastomótica/etiología , Fuga Anastomótica/cirugía , Biomarcadores , Humanos , Ileostomía/efectos adversos , Estudios Prospectivos , Neoplasias del Recto/complicaciones , Neoplasias del Recto/cirugía , Estudios Retrospectivos
11.
Neurotoxicol Teratol ; 89: 107039, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34737154

RESUMEN

Valproic acid (VPA) is a widely prescribed medication that has traditionally been used to treat epilepsy, yet embryonic exposure to VPA increases the risk of the fetus developing neural tube defects (NTDs). While the mechanism by which VPA causes NTDs is unknown, we hypothesize that VPA causes dysmorphogenesis through the disruption of redox-sensitive signaling pathways that are critical for proper embryonic development, and that protection from the redox disruption may decrease the prevalence of NTDs. Time-bred CD-1 mice were treated with 3H-1,2-dithiole-3-thione (D3T), an inducer of nuclear factor erythroid 2-related factor 2 (NRF2)-a transcription factor that activates the intracellular antioxidant response to prevent redox disruptions. Embryos were then collected for whole embryo culture and subsequently treated with VPA in vitro. The glutathione (GSH)/glutathione disulfide (GSSG) redox potential (Eh), a measure of the intracellular redox environment, was measured in the developing mouse embryos. Embryos treated with VPA exhibited a transiently oxidizing GSH/GSSG Eh, while those that received D3T pretreatment prior to VPA exposure showed no differences compared to controls. Moving to an in utero mouse model, time-bred C57BL/6 J dams were pretreated with or without D3T and then exposed to VPA, after which all embryos were collected for morphological analyses. The prevalence of open neural tubes in embryos treated with VPA significantly decreased with D3T pretreatment, as did the severity of the observed defects evaluated by a morphological assessment. These data show that NRF2 induction via D3T pretreatment protects against VPA-induced redox dysregulation and decreases the prevalence of NTDs in developing mouse embryos.


Asunto(s)
Defectos del Tubo Neural , Ácido Valproico , Animales , Embrión de Mamíferos , Femenino , Ratones , Ratones Endogámicos C57BL , Factor 2 Relacionado con NF-E2/metabolismo , Defectos del Tubo Neural/inducido químicamente , Defectos del Tubo Neural/metabolismo , Defectos del Tubo Neural/prevención & control , Embarazo , Ácido Valproico/toxicidad
12.
Ann Coloproctol ; 38(2): 124-132, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33445840

RESUMEN

PURPOSE: Anastomotic leakage (AL) is the anathema of colorectal surgery. Its occurrence leads to increased morbidity and mortality and a prolonged hospital stay. Much work has gone into studying various biomarkers in drain fluid to facilitate early detection of AL. This stage 2a development study aims to assess the safety and feasibility of reliably detecting the iodine in Gastrografin (GG; Bayer Australia Ltd.) in drain fluid and stool samples by dual-energy computed tomography (DECT). METHODS: This is a prospective, observational, controlled, consecutive cohort study establishing the safety and feasibility of the detection of GG in surgical drain fluid and stool as a biomarker of AL when patients with a low pelvic colorectal anastomosis undergo luminal flushing of the rectal tube with GG. RESULTS: Ten consecutive patients were allocated to the saline flush group and the following 10 to the GG flush group. Three patients in the saline flush group developed an AL. One patient in the GG flush group developed an AL. An elevation in the drain fluid GG was detected using DECT on the day of clinical deterioration. None of the patients in the control group were found to have a positive result on DECT. CONCLUSION: This study demonstrates the safety of a novel approach to the early detection of AL from extraperitoneal colorectal anastomoses. The technique requires validation in a larger cohort and a multicenter study is planned to investigate the efficacy of GG rectal tube flushes as an early biomarker of AL in low pelvic anastomoses.

13.
Reprod Toxicol ; 101: 81-92, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33713778

RESUMEN

Redox regulation during metazoan development ensures that coordinated metabolic reprogramming and developmental signaling are orchestrated with high fidelity in the hypoxic embryonic environment. Valproic acid (VPA), an anti-seizure medication, is known to increase markers of oxidation and also increase the risk of neural tube defects (NTDs) when taken during pregnancy. It is unknown, however, whether oxidation plays a direct role in failed neural tube closure (NTC). Spatial and temporal fluctuations in total glutathione (GSH) and total cysteine (Cys) redox steady states were seen during a 24 h period of CD-1 mouse organogenesis in untreated conceptuses and following exposure to VPA and the Nrf2 antioxidant pathway inducer, 1,2-dithiole-3-thione (D3T). Glutathione, glutathione disulfide (GSSG), and Cys, cystine (CySS) concentrations, measured in conceptal tissues (embryo/visceral yolk sac) and fluids (yolk sac fluid/amniotic fluid) showed that VPA did not cause extensive and prolonged oxidation during the period of NTC, but instead produced transient periods of oxidation, as assessed by GSH:GSSG redox potentials, which revealed oxidation in all four conceptal compartments at 4, 10, and 14 h, corresponding to the period of heartbeat activation and NTC. Other changes were tissue and time specific. VPA treatment also reduced total FITC-Ab clearance from the medium over 3 h, indicating potential disruption of nutritive amino acid supply. Overall, these results indicated that VPA's ability to affect cellular redox status may be limited to tissue-specific windows of sensitivity during the period of NTC. The safety evaluation of drugs used during pregnancy should consider time and tissue specific redox factors.


Asunto(s)
Anticonvulsivantes/toxicidad , Antineoplásicos/toxicidad , Embrión de Mamíferos/efectos de los fármacos , Tionas/toxicidad , Tiofenos/toxicidad , Ácido Valproico/toxicidad , Aminoácidos/metabolismo , Animales , Cisteína/metabolismo , Embrión de Mamíferos/metabolismo , Femenino , Glutamato-Cisteína Ligasa/genética , Glutamato-Cisteína Ligasa/metabolismo , Glutatión/metabolismo , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Intercambio Materno-Fetal , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Ratones , NAD(P)H Deshidrogenasa (Quinona)/genética , NAD(P)H Deshidrogenasa (Quinona)/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Organogénesis/efectos de los fármacos , Oxidación-Reducción , Embarazo
14.
Beilstein J Org Chem ; 17: 156-165, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33564326

RESUMEN

In our hands, efficient access to the 4-amino-3-carboxamide disubstituted pyridine-2(1H)-one kinase hinge-binder motif proved to be more challenging than anticipated requiring a significant investment in route scouting and optimization. This full paper focuses on the synthesis issues that we encountered during our route exploration and the original solutions we found that helped us to identify two optimized library-style processes to prepare our large kinase inhibitor library.

15.
Epilepsy Behav ; 115: 107637, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33317940

RESUMEN

INTRODUCTION: The SUDEP and Seizure Safety Checklist ("Checklist") is a risk factors Checklist based around a person with epilepsy (PWE) demographics, seizure, physical, psychological, and lifestyle issues. The Checklist provides a cumulative picture of current risk when applied to a PWE. This study compares and contrasts risk factors of PWE in primary versus secondary care. METHODS: The Checklist was applied to all PWE registered in four primary care practices in central Cornwall UK (pop: 120,000). Individual, modifiable, non-modifiable, and total risk factors and scores were compared between PWE open to secondary care and those not. Statistical tests were used to calculate significance of individual risk factors in primary or secondary care, to compare the total risk scores between care settings and to find the frequency differences of each risk factor between primary practices. RESULTS: People with total and non-modifiable risk scores were higher in secondary care (both p < 0.001). However, modifiable risk scores were higher in primary care (p < 0.001). Psychiatric concerns were the most prevalent modifiable risk factor in primary care. There were significant differences in the risk profiles between all four primary care practices. CONCLUSION: This study highlights that there is a lack of clarity on who is referred to secondary care and when. There needs to be an evidence-based system to allow for a bidirectional flow of PWE considering their fluctuating risk. The Checklist can be a decision support tool to enable this.


Asunto(s)
Muerte Súbita e Inesperada en la Epilepsia , Muerte Súbita/epidemiología , Muerte Súbita/etiología , Humanos , Factores de Riesgo , Atención Secundaria de Salud , Convulsiones/epidemiología
16.
Reprod Sci ; 27(11): 2104-2114, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32542535

RESUMEN

Significant gaps exist in our knowledge of how cellular redox status, sometimes referred to as oxidative stress, impacts placental trophoblasts. The present study used tert-butyl hydroperoxide (TBHP) as a known generator of reactive oxygen species (ROS) in the extravillous trophoblast cell line HTR-8/SVneo to examine the role of cellular redox disruption of prostaglandin E2 (PGE2) and the cytokine IL-6 in cell death. Cells were exposed to 0, 12.5, 25, or 50 µM TBHP for 4, 8, and 24 h to ascertain effects on cell viability, caspase 3/7 activity, PGE2 release, PTGS2 mRNA expression, and IL-6 release. Experiments with inhibitors included the cyclooxygenase inhibitor indomethacin, mitogen-activated protein kinase inhibitors (PD169316, U0126, or SP600125), or treatments to counter expected consequences of TBHP-stimulated generation of ROS (deferoxamine [DFO], butylated hydroxyanisole [BHA], and N,N'-diphenyl-1,4-phenylenediamine [DPPD]) using 24-h exposure to 50 µM TBHP. Cell viability, measured by ATP content, decreased 24% relative to controls with a 24-h exposure to 50 µM TBHP, but not at lower TBHP concentrations nor at earlier time points. Exposure to 50 µM TBHP increased caspase 3/7 activity, an indicator of apoptosis, after 8 and 24 h. Antioxidant treatment markedly reduced TBHP-stimulated caspase 3/7 activity, PGE2 release, and IL-6 release. TBHP-stimulated IL-6 release was blocked by PD169316 but unaltered by indomethacin. These data suggest that TBHP-stimulated IL-6 release and caspase 3/7 activation were independent of PGE2 yet were interrupted by treatments with known antioxidant properties, providing new insight into relationships between PGE2, IL-6, and apoptosis under conditions of chemically induced cellular oxidation.


Asunto(s)
Apoptosis , Dinoprostona/metabolismo , Interleucina-6/metabolismo , Placenta/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Trofoblastos/metabolismo , terc-Butilhidroperóxido/administración & dosificación , Apoptosis/efectos de los fármacos , Línea Celular , Femenino , Humanos , Placenta/efectos de los fármacos , Embarazo , Trofoblastos/efectos de los fármacos
17.
Toxicology ; 436: 152427, 2020 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-32145346

RESUMEN

The hypothesis that in utero exposures to low levels of trichloroethylene (TCE) may increase the risk of congenital heart defects (CHDs) in offspring remains a subject of substantial controversy within the scientific community due primarily to the reliance on an inconsistent and unreproducible experimental study in rats. To build on previous assessments that have primarily focused on epidemiological and experimental animal studies in developing conclusions, the objective of the current study is to conduct a systematic evaluation of mechanistic data related to in utero exposures to TCE and the development of CHDs. The evidence base was heterogeneous; 79 mechanistic datasets were identified, characterizing endpoints which ranged from molecular to organismal responses in seven species, involving both in vivo and in vitro study designs in mammalian and non-mammalian models. Of these, 24 datasets were considered reliable following critical appraisal using a study quality tool that employs metrics specific to the study type. Subsequent synthesis and integration demonstrated that the available mechanistic data: 1) did not support the potential for CHD hazard in humans, 2) did not support the biological plausibility of a response in humans based on organization via a putative adverse outcome pathway for valvulo-septal cardiac defects, and 3) were not suitable for serving as candidate studies in risk assessment. Findings supportive of an association were generally limited to in ovo chicken studies, in which TCE was administered in high concentration solutions via direct injection. Results of these in ovo studies were difficult to interpret for human health risk assessment given the lack of generalizability of the study models (including dose relevance, species-specific biological differences, variations in the construct of the study design, etc.). When the mechanistic data are integrated with findings from previous evaluations of human and animal evidence streams, the totality of evidence does not support CHDs as a critical effect in TCE human health risk assessment.


Asunto(s)
Corazón Fetal/efectos de los fármacos , Cardiopatías Congénitas/inducido químicamente , Exposición Materna/efectos adversos , Solventes/toxicidad , Pruebas de Toxicidad , Tricloroetileno/toxicidad , Animales , Determinación de Punto Final , Femenino , Cardiopatías Congénitas/embriología , Humanos , Embarazo , Medición de Riesgo
18.
Soft Matter ; 16(15): 3628-3641, 2020 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-32222755

RESUMEN

Dynamic covalent hydrogels crosslinked by boronate ester bonds are promising materials for biomedical applications. However, little is known about the impact of the crosslink structure on the mechanical behaviour of the resulting network. Herein, we provide a mechanistic study on boronate ester crosslinking upon mixing hyaluronic acid (HA) backbones modified, on the one hand, with two different arylboronic acids, and on the other hand, with three different saccharide units. Combining rheology, NMR and computational analysis, we demonstrate that carefully selecting the arylboronic-polyol couple allows for tuning the thermodynamics and molecular exchange kinetics of the boronate ester bond, thereby controlling the rheological properties of the gel. In particular, we report the formation of "strong" gels (i.e. featuring slow relaxation dynamics) through the formation of original complex structures (tridentate or bidentate complexes). These findings offer new prospects for the rational design of hydrogel scaffolds with tailored mechanical response.


Asunto(s)
Ácidos Borónicos/química , Ácido Hialurónico/química , Hidrogeles/química , Concentración de Iones de Hidrógeno , Resonancia Magnética Nuclear Biomolecular , Reología
19.
Antioxid Redox Signal ; 32(10): 715-740, 2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-31891515

RESUMEN

Significance: The geological record shows that as atmospheric O2 levels increased, it concomitantly coincided with the evolution of metazoans. More complex, higher organisms contain a more cysteine-rich proteome, potentially as a means to regulate homeostatic responses in a more O2-rich environment. Regulation of redox-sensitive processes to control development is likely to be evolutionarily conserved. Recent Advances: During early embryonic development, the conceptus is exposed to varying levels of O2. Oxygen and redox-sensitive elements can be regulated to promote normal development, defined as changes to cellular mass, morphology, biochemistry, and function, suggesting that O2 is a developmental morphogen. During periods of O2 fluctuation, embryos are "reprogrammed," on the genomic and metabolic levels. Reprogramming imparts changes to particular redox couples (nodes) that would support specific post-translational modifications (PTMs), targeting the cysteine proteome to regulate protein function and development. Critical Issues: Major developmental events such as stem cell expansion, proliferation, differentiation, migration, and cell fate decisions are controlled through oxidative PTMs of cysteine-based redox nodes. As such, timely coordinated redox regulation of these events yields normal developmental outcomes and viable species reproduction. Disruption of normal redox signaling can produce adverse developmental outcomes. Future Directions: Furthering our understanding of the redox-sensitive processes/pathways, the nature of the regulatory PTMs involved in development and periods of activation/sensitivity to specific developmental pathways would greatly support the theory of redox regulation of development, and would also provide rationale and direction to more fully comprehend poor developmental outcomes, such as dysmorphogenesis, functional deficits, and preterm embryonic death.


Asunto(s)
Evolución Biológica , Ambiente , Oxígeno/metabolismo , Animales , Humanos , Oxidación-Reducción , Estrés Oxidativo , Procesamiento Proteico-Postraduccional
20.
Biomacromolecules ; 21(1): 230-239, 2020 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-31609592

RESUMEN

We demonstrate here, for the first time, formation of injectable dynamic covalent hydrogels at physiological pH using benzoxaborin-saccharide complexation as a reversible cross-linking method. The gels were prepared by simply mixing hyaluronic acid modified with an original boronic acid derivative, 3,4-dihydro-2H-benzo[e][1,2]oxaborinin-2-ol (1,2-ABORIN), and HA functionalized with 1-amino-1-deoxy-d-fructose. Dynamic rheological experiments confirmed the gel-like behavior (storage modulus (G') > loss modulus (G″) in the frequency window explored) for the designed HA-1,2-ABORIN/HA-fructose network. Furthermore, this hydrogel exhibited excellent self-healing and injectability behaviors in aqueous conditions and was found to be responsive to pH. Additionally, fibroblast cells encapsulated in the HA network showed high viability (>80% after 7 days of cell culture), as monitored by Live/Dead staining. Taken together, this new class of boronate ester cross-linked hydrogel provides promising future for diverse biomedical applications.


Asunto(s)
Técnicas de Cultivo de Célula/métodos , Ácido Hialurónico/química , Hidrogeles/química , Animales , Ácidos Borínicos/química , Ácidos Borónicos/química , Técnicas de Cultivo de Célula/instrumentación , Supervivencia Celular , Fibroblastos/citología , Fructosa/química , Concentración de Iones de Hidrógeno , Inyecciones , Espectroscopía de Resonancia Magnética , Ratones , Reología
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