MIBiG 3.0: a community-driven effort to annotate experimentally validated biosynthetic gene clusters.

With an ever-increasing amount of (meta)genomic data being deposited in sequence databases, (meta)genome mining for natural product biosynthetic pathways occupies a critical role in the discovery of novel pharmaceutical drugs, crop protection agents and biomaterials. The genes that encode these pathways are often organised into biosynthetic gene clusters (BGCs). In 2015, we defined the Minimum Information about a Biosynthetic Gene cluster (MIBiG): a standardised data format that describes the minimally required information to uniquely characterise a BGC. We simultaneously constructed an accompanying online database of BGCs, which has since been widely used by the community as a reference dataset for BGCs and was expanded to 2021 entries in 2019 (MIBiG 2.0). Here, we describe MIBiG 3.0, a database update comprising large-scale validation and re-annotation of existing entries and 661 new entries. Particular attention was paid to the annotation of compound structures and biological activities, as well as protein domain selectivities. Together, these new features keep the database up-to-date, and will provide new opportunities for the scientific community to use its freely available data, e.g. for the training of new machine learning models to predict sequence-structure-function relationships for diverse natural products. MIBiG 3.0 is accessible online at https://mibig.secondarymetabolites.org/.

The impact of heterotopic ovarian tissue transplantation with varied volumes on reproductive endocrine function in oophorectomized rats.

BACKGROUND: This study aimed to investigate the effects of different volumes of ovarian tissue transplantation on the reproductive endocrine function of rats after oophorectomy. METHODS: Female rats were selected to establish a castration model and then underwent different volumes of ovarian tissue transplantation. Group I served as the sham operation group. The transplantation group was divided into five subgroups based on the calculated ratio of ovarian weight to body weight in normal female rats, δ = (2.52 ± 0.17) ×10-4: Group II: transplanted ovarian volume was δ; Group III: 0.75δ; Group IV: 0.5δ; Group V: 0.25δ; Group VI: without ovarian transplantation. The post-transplant oestrous cycle recovery was observed, and blood samples were collected every 2 weeks to measure serum hormone levels. Histological evaluation was performed at the end of the observation period. RESULTS: Rats in Group V exhibited disrupted oestrous cycles after transplantation, which were significantly longer than those in Group I. Rats in Groups II, III, and IV showed no cyclic changes. At 6 weeks post-transplantation, rats in Group V had lower E2 and AMH levels and higher FSH levels compared to Group I. The uterine wet weight and the number of normal follicles in Group V were significantly lower than those in Group I, but the number of atretic follicles was higher than in Group I. CONCLUSION: The larger ovarian tissue transplantation resulted in a faster recovery with a higher survival rate of the uterus and normal follicles, compared to smaller ovarian tissue transplantation.

With advancements in science and technology, ovarian transplantation techniques have become increasingly mature. However, there are still many questions that need to be addressed. For instance, the large size of the transplanted ovarian tissues may cause over-recruitment of the primordial follicles. When the transplanted ovarian tissue is too small, it can only exert limited functionality and may not meet the patient's needs. This study aimed to investigate the effects of different volumes of ovarian tissue transplantation on the reproductive endocrine function in rats after oophorectomy, and to provide a theoretical basis for determining the minimum effective volume of heterotopic ovarian tissue transplantation.

Auto-setting multi-soliton temporal spacing in a fiber laser by a hybrid GA-PSO algorithm.

Multi-soliton operation in fiber lasers is a promising platform for the investigation of soliton interaction dynamics and high repetition-rate pulse. However, owing to the complex interaction process, precisely manipulating the temporal spacing of multiple solitons in a fiber laser is still challenging. Herein, we propose an automatic way to control the temporal spacing of multi-soliton operation in an ultrafast fiber laser by a hybrid genetic algorithm-particle swarm optimization (GA-PSO) algorithm. Relying on the intelligent adjustment of the electronic polarization controller (EPC), the on-demand temporal spacing of the double solitons can be effectively achieved. In particular, the harmonic mode locking with equal temporal spacing of double solitons is also obtained. Our approach provides a promising way to explore nonlinear soliton dynamics in optical systems and optimize the performance of ultrafast fiber lasers.

Critical Role of Monooxygenase in Biodegradation of 2,4,6-Trinitrotoluene by Buttiauxella sp. S19-1.

2,4,6-Trinitrotoluene (TNT) is an aromatic pollutant that is difficult to be degraded in the natural environment. The screening of efficient degrading bacteria for bioremediation of TNT has received much attention from scholars. In this paper, transcriptome analysis of the efficient degrading bacterium Buttiauxella sp. S19-1 revealed that the monooxygenase gene (BuMO) was significantly up-regulated during TNT degradation. S-ΔMO (absence of BuMO gene in S19-1 mutant) degraded TNT 1.66-fold less efficiently than strain S19-1 (from 71.2% to 42.9%), and E-MO mutant (Escherichia coli BuMO-expressing strain) increased the efficiency of TNT degradation 1.33-fold (from 52.1% to 69.5%) for 9 h at 180 rpm at 27 °C in LB medium with 1.4 µg·mL-1 TNT. We predicted the structure of BuMO and purified recombinant BuMO (rBuMO). Its specific activity was 1.81 µmol·min-1·mg-1 protein at pH 7.5 and 35 °C. The results of gas chromatography mass spectrometry (GC-MS) analysis indicated that 4-amino-2,6-dinitrotoluene (ADNT) is a metabolite of TNT biodegradation. We speculate that MO is involved in catalysis in the bacterial degradation pathway of TNT in TNT-polluted environment.

Association between admission hypothermia and outcomes in very low birth weight infants in China: a multicentre prospective study.

BACKGROUND: The objective of this prospective, multicentre, observational cohort study was to evaluate the association between admission hypothermia and neonatal outcomes in very low-birth weight (VLBW) infants in multiple neonatal intensive care units (NICUs) in China. METHODS: Since January 1, 2018, a neonatal homogeneous cooperative research platform-Shandong Neonatal Network (SNN) has been established. The platform collects clinical data in a prospective manner on preterm infants with birth weights (BWs) < 1500 g and gestational ages (GAs) < 34 weeks born in 28 NICUs in Shandong Province. These infants were divided into normothermia, mild or moderate/severe hypothermia groups according to the World Health Organization (WHO) classifications of hypothermia. Associations between outcomes and hypothermia were tested in a bivariate analysis, followed by a logistic regression analysis. RESULTS: A total of 1247 VLBW infants were included in this analysis, of which 1100 infants (88.2%) were included in the hypothermia group, 554 infants (44.4%) in the mild hypothermia group and 546 infants (43.8%) in the moderate/severe hypothermia group. Small for gestational age (SGA), caesarean section, a low Apgar score at 5 min and intubation in the delivery room (DR) were related to admission hypothermia (AH). Mortality was the lowest when their admission temperature was 36.5 ~ 37.5 °C, and after adjustment for maternal and infant characteristics, mortality was significantly associated with AH. Compared with infants with normothermia (36.5 ~ 37.5 °C), the adjusted ORs of all deaths increased to 4.148 (95% CI 1.505-11.437) and 1.806 (95% CI 0.651-5.009) for infants with moderate/severe hypothermia and mild hypothermia, respectively. AH was also associated with a high likelihood of respiratory distress syndrome (RDS), intraventricular haemorrhage (IVH), and late-onset neonatal sepsis (LOS). CONCLUSIONS: AH is still very high in VLBW infants in NICUs in China. SGA, caesarean section, a low Apgar score at 5 min and intubation in the DR were associated with increased odds of hypothermia. Moderate/severe hypothermia was associated with mortality and poor outcomes, such as RDS, IVH, LOS.

Investigation of the mechanism of the SpnF-catalyzed [4+2]-cycloaddition reaction in the biosynthesis of spinosyn A.

The Diels-Alder reaction is one of the most common methods to chemically synthesize a six-membered carbocycle. While it has long been speculated that the cyclohexene moiety found in many secondary metabolites is also introduced via similar chemistry, the enzyme SpnF involved in the biosynthesis of the insecticide spinosyn A in Saccharopolyspora spinosa is the first enzyme for which catalysis of an intramolecular [Formula: see text]-cycloaddition has been experimentally verified as its only known function. Since its discovery, a number of additional standalone [Formula: see text]-cyclases have been reported as potential Diels-Alderases; however, whether their catalytic cycles involve a concerted or stepwise cyclization mechanism has not been addressed experimentally. Here, we report direct experimental interrogation of the reaction coordinate for the [Formula: see text]-carbocyclase SpnF via the measurement of [Formula: see text]-secondary deuterium kinetic isotope effects (KIEs) at all sites of [Formula: see text] rehybridization for both the nonenzymatic and enzyme-catalyzed cyclization of the SpnF substrate. The measured KIEs for the nonenzymatic reaction are consistent with previous computational results implicating an intermediary state between formation of the first and second carbon-carbon bonds. The KIEs measured for the enzymatic reaction suggest a similar mechanism of cyclization within the enzyme active site; however, there is evidence that conformational restriction of the substrate may play a role in catalysis.

The Amipurimycin and Miharamycin Biosynthetic Gene Clusters: Unraveling the Origins of 2-Aminopurinyl Peptidyl Nucleoside Antibiotics.

Peptidyl nucleoside antibiotics (PNAs) are a diverse class of natural products with promising biomedical activities. These compounds have tripartite structures composed of a core saccharide, a nucleobase, and one or more amino acids. In particular, amipurimycin and the miharamycins are novel 2-aminopurinyl PNAs with complex nine-carbon core saccharides and include the unusual amino acids (-)-cispentacin and N5-hydroxyarginine, respectively. Despite their interesting structures and properties, these PNAs have heretofore eluded biochemical scrutiny. Herein is reported the discovery and initial characterization of the miharamycin gene cluster in Streptomyces miharaensis (mhr) and the amipurimycin gene cluster (amc) in Streptomyces novoguineensis and Streptomyces sp. SN-C1. The gene clusters were identified using a comparative genomics approach, and heterologous expression of the amc cluster as well as gene interruption experiments in the mhr cluster support their role in the biosynthesis of amipurimycin and the miharamycins, respectively. The mhr and amc biosynthetic gene clusters characterized encode enzymes typical of polyketide biosynthesis instead of enzymes commonly associated with PNA biosynthesis, which, along with labeled precursor feeding studies, implies that the core saccharides found in the miharamycins and amipurimycin are partially assembled as polyketides rather than derived solely from carbohydrates. Furthermore, in vitro analysis of Mhr20 and Amc18 established their roles as ATP-grasp ligases involved in the attachment of the pendant amino acids found in these PNAs, and Mhr24 was found to be an unusual hydroxylase involved in the biosynthesis of N5-hydroxyarginine. Finally, analysis of the amc cluster and feeding studies also led to the proposal of a biosynthetic pathway for (-)-cispentacin.

Bacterial terpene biosynthesis: challenges and opportunities for pathway engineering.

Terpenoids are the largest and structurally most diverse class of natural products. They possess potent and specific biological activity in multiple assays and against diseases, including cancer and malaria as notable examples. Although the number of characterized terpenoid molecules is huge, our knowledge of how they are biosynthesized is limited, particularly when compared to the well-studied thiotemplate assembly lines. Bacteria have only recently been recognized as having the genetic potential to biosynthesize a large number of complex terpenoids, but our current ability to associate genetic potential with molecular structure is severely restricted. The canonical terpene biosynthetic pathway uses a single enzyme to form a cyclized hydrocarbon backbone followed by modifications with a suite of tailoring enzymes that can generate dozens of different products from a single backbone. This functional promiscuity of terpene biosynthetic pathways renders terpene biosynthesis susceptible to rational pathway engineering using the latest developments in the field of synthetic biology. These engineered pathways will not only facilitate the rational creation of both known and novel terpenoids, their development will deepen our understanding of a significant branch of biosynthesis. The biosynthetic insights gained will likely empower a greater degree of engineering proficiency for non-natural terpene biosynthetic pathways and pave the way towards the biotechnological production of high value terpenoids.

Mechanistic Implications of the Deamination of TDP-4-amino-4-deoxy-d-fucose Catalyzed by the Radical SAM Enzyme DesII.

DesII is a radical SAM lyase that catalyzes a deamination reaction during the biosynthesis of desosamine in Streptomyces venezuelae. Competing mechanistic hypotheses for this radical-mediated reaction are differentiated according to whether a 1,2-migration takes place and the timing of proton abstraction following generation of a substrate α-hydroxyalkyl radical intermediate. In this study, the deuterated C4 epimer of the natural substrate, TDP-4-amino-4-deoxy-d-[3-2H]fucose, was prepared and shown to be a substrate for DesII undergoing deamination alone with a specific activity that is only marginally reduced (∼3-fold) with respect to that of deamination of the natural substrate. Furthermore, pH titration of the deamination reaction implicates the presence of a hydron acceptor that facilitates catalysis but does not appear to be necessary. On the basis of these as well as previously reported results, a mechanism involving direct elimination of ammonium with concerted proton transfer to the nucleofuge from the adjacent α-hydroxyalkyl radical is proposed.

Improvement of indoor air quality in pet shop using gaseous chlorine dioxide.

Many studies have shown that pet shops have a high concentration of bioaerosols. Thus, effective disinfection protocols are essential to protect the pet shop staff and visitors to the store. The present study examines the effectiveness of gaseous chlorine dioxide (ClO2) fogging in minimizing the residual bacteria and fungi levels in a typical pet shop in Taiwan consisting of a commodity area, a lodging area, and a grooming area. This investigation uses three disinfection modes (DMs) according to different disinfection periods, namely once every hour (1DM), once every 2 h (2DM), and once every 3 h (3DM). The bacteria and fungi concentrations are measured before and after disinfection treatment, and the effectiveness of each disinfection mode is evaluated using standard statistical techniques. To assess the effect of the environmental factors on the disinfection efficiency, measurements are taken of temperature, relative humidity, airflow velocity, the carbon dioxide concentration, the PM1, PM2.5, PM7, PM10, and TSP level at each sampling locations. The results reveal that the effectiveness of the three disinfection modes depends on both the environmental parameters and the use of the three areas (e.g., commodity, lodging, or grooming). Hence, the choice of disinfection method should be adjusted accordingly. For all three disinfection modes, a faster air velocity is beneficial in spreading the disinfectant throughout the indoor space and improving the disinfection performance. Overall, the results presented in this study confirm that gaseous chlorine dioxide disinfection improves the air quality in the pet shop interior, and thus beneficial in safeguarding the health of the pet shop staff and visitors.

Identification and Interrogation of the Herbicidin Biosynthetic Gene Cluster: First Insight into the Biosynthesis of a Rare Undecose Nucleoside Antibiotic.

Herbicidins are adenosine-based nucleoside antibiotics with an unusual tricyclic undecose core decorated with a (5-hydroxy)tiglyl moiety. Feeding studies are herein reported demonstrating that the tricyclic core is derived from d-glucose and d-ribose, whereas the tiglyl moiety is derived from an intermediate of l-isoleucine catabolism. Identification of the gene cluster for herbicidin A biosynthesis in Streptomyces sp. L-9-10 as well as its verification by heterologous expression in a nonproducing host are described, and the results of in vitro characterization of a carboxyl methyltransferase encoded in the cluster, Her8, are presented. Based on these observations, a biosynthetic pathway is proposed for herbicidins.

The anti-proliferative effects of oleanolic acid on A7r5 cells-Role of UCP2 and downstream FGF-2/p53/TSP-1.

Vascular smooth muscle cell (VSMC) proliferation is a major contributor to atherosclerosis. This study investigated the inhibitory effects of oleanolic acid (OA) against oxidized low-density lipoprotein (ox-LDL)-induced VSMC proliferation in A7r5 cells and explored underlying molecular mechanism. The cell proliferation was quantified with cell counting kit-8 (CCK-8), in which ox-LDL significantly increased A7r5 cells proliferation, while OA pretreatment effectively alleviated such changes without inducing overt cytotoxicity, as indicated by lactate dehydrogenase (LDH) assay. Quantitative real-time RT-PCR (qRT-PCR) and Western blotting revealed increased UCP2 and FGF-2 expression levels as well as decreased p53 and TSP-1 expression levels in A7r5 cells following ox-LDL exposure, while OA pretreatment reversed such changes. Furthermore, inhibiting UCP2 with genipin remarkably reversed the changes in the expression levels of FGF-2, p53, and TSP-1 induced by ox-LDL exposure; silencing FGF-2 with siRNA did not significantly change the expression levels of UCP2 but effectively reversed the changes in the expression levels of p53 and TSP-1, and activation of p53 with PRIMA-1 only significantly affected the changes in the expression levels of TSP-1, but not in UCP2 or FGF-2, suggesting a UCP-2/FGF-2/p53/TSP-1 signaling in A7r5 cells response to ox-LDL exposure. Additionally, co-treatment of OA and genipin exhibited similar effects to the expression levels of UCP2, FGF-2, p53, and TSP-1 as OA or genipin solo treatment in ox-LDL-exposed A7r5 cells, suggesting the involvement of UCP-2/FGF-2/p53/TSP-1 in the mechanism of OA. In conclusion, OA inhibits ox-LDL-induced VSMC proliferation in A7r5 cells, the mechanism involves the changes in UCP-2/FGF-2/p53/TSP-1.

The Roles of Reactive Oxygen Species and Nitric Oxide in Perfluorooctanoic Acid-Induced Developmental Cardiotoxicity and l-Carnitine Mediated Protection.

Perfluorooctanoic acid (PFOA) is an environmental contaminant that could induce developmental cardiotoxicity in a chicken embryo, which may be alleviated by l-carnitine. To explore the roles of reactive oxygen species (ROS) and nitric oxide (NO) in such changes and the potential effects of l-carnitine, fertile chicken eggs were exposed to PFOA via an air cell injection, with or without l-carnitine co-treatment. The ROS and NO levels in chicken embryo hearts were determined with electron spin resonance (ESR), and the protein levels of the nuclear factor κ-light chain-enhancer of activated B cells (NF-κB) p65 and inducible nitric oxide synthase (iNOS) in chicken embryo hearts were assessed with western blotting. The results of ESR indicated that PFOA exposure induced an elevation in the ROS levels in ED19 chicken embryo hearts and hatchling chicken hearts, while l-carnitine could alleviate such changes. Meanwhile, increased NO levels were observed in ED19 embryo hearts and hatchling hearts following PFOA exposure, while l-carnitine co-treatment exerted modulatory effects. Western blotting revealed that p65 translocation in ED19 embryo hearts and hatchling hearts was enhanced by PFOA, while l-carnitine co-treatment alleviated such changes. iNOS expression levels in ED19 embryo hearts followed the same pattern as NO levels, while a suppression of expression was observed in hatchling hearts exposed to PFOA. ROS/NF-κB p65 and iNOS/NO seem to be involved in the late stage (ED19 and post hatch) of PFOA-induced developmental cardiotoxicity in a chicken embryo. l-carnitine could exert anti-oxidant and NO modulatory effects in the developing chicken embryo hearts, which likely contribute to its cardioprotective effects.

Specific Cancer Cytosolic Drug Delivery Triggered by Reactive Oxygen Species-Responsive Micelles.

Cytosolic drug delivery, a major route in cancer therapy, is limited by the lack of efficient and safe endosomal escape techniques. Herein, we demonstrate a reactive oxygen species (ROS)-responsive micelle composed of methoxy polyethylene glycol-b-poly(diethyl sulfide) (mPEG-PS) copolymers which can induce specific endosome escape in cancer cells by changes in the hydrophobicity of copolymers. Owing to the more ROS levels in cancer cells than normal cells, the copolymers can be converted into more hydrophilic and insert into and destabilize the cancer intracellular endosome membrane after cellular uptake. More importantly, we show that acid-intolerant drugs successfully maintain their bioactivity and cause selective cytotoxicity for cancer cells over normal cells. Our results suggest that the endosomal escape induced by hydrophobic-hydrophilic exchange of copolymers has great potential to locally and efficiently deliver biological agents (e.g., proteins and genes) in the cancer cell cytosol.

Mechanistic Investigation of the Radical S-Adenosyl-L-methionine Enzyme DesII Using Fluorinated Analogues.

DesII is a radical S-adenosyl-l-methionine (SAM) enzyme that can act as a deaminase or a dehydrogenase depending on the nature of its TDP-sugar substrate. Previous work has implicated a substrate-derived, C3-centered α-hydroxyalkyl radical as a key intermediate during catalysis. Although deprotonation of the α-hydroxyalkyl radical has been shown to be important for dehydrogenation, much less is known regarding the course of the deamination reaction. To investigate the role played by the C3 hydroxyl during deamination, 3-deutero-3-fluoro analogues of both substrates were prepared and characterized with DesII. In neither case was deamination or oxidation observed; however, in both cases deuterium was efficiently exchanged between the substrate analogues and SAM. These results imply that the C3 hydroxyl plays a key role in both reactions­thereby arguing against a 1,2-migration mechanism of deamination­and that homolysis of SAM concomitant with H atom abstraction from the substrate is readily reversible when forward partitioning is inhibited.

Mechanistic consequences of chiral radical clock probes: analysis of the mononuclear non-heme iron enzyme HppE with 2-hydroxy-3-methylenecyclopropyl radical clock substrates.

(S)-2-Hydroxypropylphosphonic acid [(S)-HPP] epoxidase (HppE) is a mononuclear iron enzyme that catalyzes the last step in the biosynthesis of the antibiotic fosfomycin. HppE also processes the (R)-enantiomer of HPP but converts it to 2-oxo-propylphosphonic acid. In this study, all four stereoisomers of 3-methylenecyclopropyl-containing substrate analogues, (2R, 3R)-8, (2R, 3S)-8, (2S, 3R)-8, and (2S, 3S)-8, were synthesized and used as radical probes to investigate the mechanism of the HppE-catalyzed reaction. Upon treatment with HppE, (2S, 3R)-8 and (2S, 3S)-8 were converted via a C1 radical intermediate to the corresponding epoxide products, as anticipated. In contrast, incubation of HppE with (2R, 3R)-8 led to enzyme inactivation, and incubation of HppE with (2R, 3S)-8 yielded the 2-keto product. The former finding is consistent with the formation of a C2 radical intermediate, where the inactivation is likely triggered by radical-induced ring cleavage of the methylenecyclopropyl group. Reaction with (2R, 3S)-8 is predicted to also proceed via a C2 radical intermediate, but no enzyme inactivation and no ring-opened product were detected. These results strongly suggest that an internal electron transfer to the iron center subsequent to C-H homolysis competes with ring-opening in the processing of the C2 radical intermediate. The different outcomes of the reactions with (2R, 3R)-8 and (2R, 3S)-8 demonstrate the need to carefully consider the chirality of substituted cyclopropyl groups as radical reporting groups in studies of enzymatic mechanisms.

Stem Cell Therapy in Neonatal Hypoxic-Ischemic Encephalopathy and Cerebral Palsy: a Bibliometric Analysis and New Strategy.

The aim of this study was to identify related scientific outputs and emerging topics of stem cells in neonatal hypoxic-ischemic encephalopathy (NHIE) and cerebral palsy (CP) through bibliometrics and literature review. All relevant publications on stem cell therapy for NHIE and CP were screened from websites and analyzed research trends. VOSviewer and CiteSpace were applied to visualize and quantitatively analyze the published literature to provide objective presentation and prediction. In addition, the clinical trials, published articles, and projects of the National Natural Science Foundation of China associated with stem cell therapy for NHIE and CP were summarized. A total of 294 publications were associated with stem cell therapy for NHIE and CP. Most publications and citations came from the USA and China. Monash University and University Medical Center Utrecht produced the most publications. Pediatric research published the most studies on stem cell therapy for NHIE and CP. Heijnen C and Kavelaars A published the most articles. Cluster analyses show that current research trend is more inclined toward the repair mechanism and clinical translation of stem cell therapy for NHIE and CP. By summarizing various studies of stem cells in NHIE and CP, it is indicated that this research direction is a hot topic at present. Furthermore, organoid transplantation, as an emerging and new therapeutic approach, brings new hope for the treatment of NHIE and CP. This study comprehensively summarized and analyzed the research trend of global stem cell therapy for NHIE and CP. It has shown a marked increase in stem cell therapy for NHIE and CP research. In the future, more efforts will be made on exploring stem cell or organoid therapy for NHIE and CP and more valuable related mechanisms of action to achieve clinical translation as soon as possible.

Unraveling the effects of prenatal anesthesia on neurodevelopment: A review of current evidence and future directions.

Human brain development is a complex, multi-stage, and sensitive process, especially during the fetal stage. Animal studies over the last two decades have highlighted the potential risks of anesthetics to the developing brain, impacting its structure and function. This has raised concerns regarding the safety of anesthesia during pregnancy and its influence on fetal brain development, garnering significant attention from the anesthesiology community. Although preclinical studies predominantly indicate the neurotoxic effects of prenatal anesthesia, these findings cannot be directly extrapolated to humans due to interspecies variations. Clinical research, constrained by ethical and technical hurdles in accessing human prenatal brain tissues, often yields conflicting results compared to preclinical data. The emergence of brain organoids as a cutting-edge research tool shows promise in modeling human brain development. When integrated with single-cell sequencing, these organoids offer insights into potential neurotoxic mechanisms triggered by prenatal anesthesia. Despite several retrospective and cohort studies exploring the clinical impact of anesthesia on brain development, many findings remain inconclusive. As such, this review synthesizes preclinical and clinical evidence on the effects of prenatal anesthesia on fetal brain development and suggests areas for future research advancement.

Dosimetric analysis of brachial plexopathy after stereotactic body radiotherapy: Significance of organ delineation.

OBJECTIVES: Examine the significance of contouring the brachial plexus (BP) for toxicity estimation and select metrics for predicting radiation-induced brachial plexopathy (RIBP) after stereotactic body radiotherapy. MATERIALS AND METHODS: Patients with planning target volume (PTV) ≤ 2 cm from the BP were eligible. The BP was contoured primarily according to the RTOG 1106 atlas, while subclavian-axillary veins (SAV) were contoured according to RTOG 0236. Apical PTVs were classified as anterior (PTV-A) or posterior (PTV-B) PTVs. Variables predicting grade 2 or higher RIBP (RIBP2) were selected through least absolute shrinkage and selection operator regression and logistic regression. RESULTS: Among 137 patients with 140 BPs (median follow-up, 32.1 months), 11 experienced RIBP2. For patients with RIBP2, the maximum physical dose to the BP (BP-Dmax) was 46.5 Gy (median; range, 35.7 to 60.7 Gy). Of these patients, 54.5 % (6/11) satisfied the RTOG limits when using SAV delineation; among them, 83.3 % (5/6) had PTV-B. For patients with PTV-B, the maximum physical dose to SAV (SAV-Dmax) was 11.2 Gy (median) lower than BP-Dmax. Maximum and 0.3 cc biologically effective doses to the BP based on the linear-quadratic-linear model (BP-BEDmax LQL and BP-BED0.3cc LQL, α/ß = 3) were selected as predictive variables with thresholds of 118 and 73 Gy, respectively. CONCLUSION: Contouring SAV may significantly underestimate the RIBP2 risk in dosimetry, especially for patients with PTV-B. BP contouring indicated BP-BED0.3cc LQL and BP-BEDmax LQL as potential predictors of RIBP2.

Brachial plexopathy following stereotactic body radiation therapy in apical lung malignancies: A dosimetric pooled analysis of individual patient data.

BACKGROUND AND OBJECTIVES: The aim of this study is to establish dosimetric constraints for the brachial plexus at risk of developing grade ≥ 2 brachial plexopathy in the context of stereotactic body radiation therapy (SBRT). PATIENTS AND METHODS: Individual patient data from 349 patients with 356 apical lung malignancies who underwent SBRT were extracted from 5 articles. The anatomical brachial plexus was delineated following the guidelines provided in the atlases developed by Hall, et al. and Kong, et al.. Patient characteristics, pertinent SBRT dosimetric parameters, and brachial plexopathy grades (according to CTCAE 4.0 or 5.0) were obtained. Normal tissue complication probability (NTCP) models were used to estimate the risk of developing grade ≥ 2 brachial plexopathy through maximum likelihood parameter fitting. RESULTS: The prescription dose/fractionation schedules for SBRT ranged from 27 to 60 Gy in 1 to 8 fractions. During a follow-up period spanning from 6 to 113 months, 22 patients (6.3 %) developed grade ≥2 brachial plexopathy (4.3 % grade 2, 2.0 % grade 3); the median time to symptoms onset after SBRT was 8 months (ranged, 3-54 months). NTCP models estimated a 10 % risk of grade ≥2 brachial plexopathy with an anatomic brachial plexus maximum dose (Dmax) of 20.7 Gy, 34.2 Gy, and 42.7 Gy in one, three, and five fractions, respectively. Similarly, the NTCP model estimates the risks of grade ≥2 brachial plexopathy as 10 % for BED Dmax at 192.3 Gy and EQD2 Dmax at 115.4 Gy with an α/ß ratio of 3, respectively. Symptom persisted after treatment in nearly half of patients diagnosed with grade ≥2 brachial plexopathy (11/22, 50 %). CONCLUSIONS: This study establishes dosimetric constraints ranging from 20.7 to 42.7 Gy across 1-5 fractions, aimed at mitigating the risk of developing grade ≥2 brachial plexopathy following SBRT. These findings provide valuable guidance for future ablative SBRT in apical lung malignancies.