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At least 343 records · Page 19Linked to original sources

CRISPR-Enabled functional genomics in hPSCs-derived neural models for autism spectrum disorder.

Autism Spectrum Disorder (ASD) is a genetically heterogeneous neurodevelopmental condition in which hundreds of individually rare risk variants converge on a small number of shared biological pathways, including synaptic scaffolding, chromatin remodeling, excitation-inhibition balance, and cellular energy metabolism. Translating this genetic heterogeneity into mechanistic insight requires experimental systems capable of interrogating individual gene functions in human-relevant neural contexts at scale. CRISPR-enabled functional genomics in human pluripotent stem cell (hPSC)-derived neural models, spanning neural progenitors, cortical and inhibitory neurons, astrocytes, microglia, and brain organoids, provides precisely this capability. By integrating pooled perturbation screens with multimodal readouts including single-cell and spatial transcriptomics, chromatin accessibility profiling, proximity labeling proteomics, multi-electrode array electrophysiology, and metabolic flux analysis, these platforms enable systematic, causal mapping of ASD gene function at system resolution. Early applications have already revealed convergent mechanisms: BAF complex disruption expands the ventral progenitor pool and biases its fate toward oligodendrocyte and interneuron lineages; ADNP loss impairs microglial synaptic pruning through altered endocytic trafficking; and mTOR pathway dysregulation in PTEN- and TSC2-perturbed models links genetic risk directly to metabolic and mitochondrial dysfunction. Computational frameworks including MIMOSCA and SCEPTRE enable causal network reconstruction and pseudotime inference from these datasets, moving the field from gene lists toward pathway-level models of ASD pathobiology. Translational applications leverage isogenic iPSC panels and variant-level base and prime editing to stratify ASD variants by functional impact, informing gene therapy design for haploinsufficient targets such as CHD8 and SCN2A via AAV or antisense oligonucleotide delivery. Remaining challenges, including model developmental immaturity, batch variability, and the difficulty of modeling polygenic risk, are addressed by a roadmap integrating spatial perturbomics, AI-driven causal inference, and population-scale standardized biobanks. This review synthesizes the current state of CRISPR-based functional genomics in human stem cell neural models as a coherent experimental framework for converting ASD genetic associations into mechanistic understanding and therapeutic opportunity.

Humans↗

Analysis of extrahepatic bile duct carcinomas according to the New American Joint Committee on Cancer staging system focused on tumor classification problems in 222 patients.

BACKGROUND: Although the sixth edition of the American Joint Committee on Cancer (AJCC) staging system for extrahepatic bile duct carcinoma was updated, the system has a problem on T classification due to its ambiguous definition of T1 as "tumor confined to bile duct histologically" and T2 as "tumor invading beyond the bile duct." METHODS: The authors considered the outermost part of the muscle layer or fibrous tissue as within the extrahepatic bile duct and considered the area starting from large clusters of adipose tissue as beyond the extrahepatic bile duct. After designing a precise definition of the extrahepatic bile duct wall, they analyzed the new AJCC staging system in 222 patients with of extrahepatic bile duct carcinomas. Then, other clinicopathologic variables for prognosis were evaluated using univariate and multivariate analyses. RESULTS: The 5-year survival rates for patients with tumors that were classified as T1, T2, T3, and T4 were 53.1%, 29.7%, 24.9%, and 0%, respectively. There was a significant difference in survival between patients with T1 tumors and T2 tumors (P < 0.05), but not between patients with T2 tumors and T3 tumors. Significant prognostic factors included depth of invasion (P < 0.005), lymph node metastasis (P < 0.005), and patient age (P < 0.05). CONCLUSIONS: Based on a proposed histologic definition, depth of invasion was practical for evaluating the prognosis of patients with middle and upper extrahepatic bile duct carcinomas. Therefore, the authors recommended changing the current pT1 and pT2 classifications to more precise pathologic terminology.

Adult↗

Spatially guided in vivo single-cell functional genomics of postnatal heart.

Understanding how spatial organization and cell-cell interactions shape gene regulatory programs is central to decoding tissue development and function. The transition at birth, marked by increased circulatory demands and rapid tissue growth, requires precise spatiotemporal coordination of cardiac maturation. In this study, we generated a high-resolution spatial and temporal atlas of the postnatal mouse heart by integrating single-nucleus RNA sequencing with image-based spatial transcriptomics. This framework revealed dynamic cellular interactions, niche-specific signaling and transcriptional programs guiding cardiomyocyte maturation. To functionally test prioritized regulators in vivo and at scale, we developed PIP-seq (probe-based indel-detectable Perturb-seq), a high-throughput platform that detects single guide RNA identity, infers gene editing and profiles transcription from fixed nuclei. Applying PIP-seq to the developing postnatal heart, we identified 21 previously uncharacterized regulators of cardiomyocyte maturation, including genes essential for sarcomere assembly, metabolic reprogramming and electrophysiological transitions. Together, our findings define how microenvironmental signals and intrinsic gene programs cooperate to guide heart maturation and establish a broadly applicable framework for functional genomics in complex tissues.

Animals↗

Brain and other nervous system tumours.

Interpretation of time trends in incidence rates for cancers of brain and other and unspecified parts of nervous system is complicated by variation in registration efficiency over time and place, statistical instability of rates, changes in the ICD classification of the tumours, variation in registration practice for the benign and unspecified tumours over time and changes in methods of diagnosis. The reader will undoubtedly have the impression that in this chapter there are too many differences in the content of the data over time and place to have confidence in any of the conclusions drawn. To derive a well documented and sustainable assessment on secular trends will require an international collaborative study collecting incidence data for the malignant, benign, uncertain and unspecified tumours of the brain and other parts of the nervous system by histology and by method of diagnosis. By providing a separate rubric for the meninges, the 10th Revision of the ICD (WHO, 1993) should--combined with the morphology rubrics of the second edition of the International Classification of Diseases-Oncology (Percy et al 1990)--make such an endeavour somewhat easier. The data presented above nevertheless suggest that, as for several other cancer sites, on the whole there has been a slow overall increase in the incidence of brain and other and unspecified nervous system neoplasms on the order of 1-2% per year over the past 30 years. Increases appear to have been greater in older people. The extent to which these increases are due to the unquestioned improvements in methods and precision of diagnosis is not clear. Birth cohort data suggest that in recent years, this influence may have been greatest for those birth cohorts born prior to 1900, and this effect is unlikely to disappear until cohorts born about 1910-1920 have passed on. There is currently little evidence to support the contention that the recent increase in older people cannot be largely explained by improvements in diagnostic methods, wider access to medical care and more intensive investigation. Further work is needed.

Adult↗

Modulation of insect Ca(v) channels by peptidic spider toxins.

Insects have a much smaller repertoire of voltage-gated calcium (Ca(V)) channels than vertebrates. Drosophila melanogaster harbors only a single ortholog of each of the vertebrate Ca(V)1, Ca(V)2, and Ca(V)3 subtypes, although its basal inventory is expanded by alternative splicing and editing of Ca(V) channel transcripts. Nevertheless, there appears to be little functional plasticity within this limited panel of insect Ca(V) channels, since severe loss-of-function mutations in genes encoding the pore-forming alpha1 subunits in Drosophila are embryonic lethal. Since the primary role of spider venom is to paralyze or kill insect prey, it is not surprising that most, if not all, spider venoms contain peptides that potently modify the activity of these functionally critical insect Ca(V) channels. Unfortunately, it has proven difficult to determine the precise ion channel subtypes recognized by these peptide toxins since insect Ca(V) channels have significantly different pharmacology to their vertebrate counterparts, and cloned insect Ca(V) channels are not available for electrophysiological studies. However, biochemical and genetic studies indicate that some of these spider toxins might ultimately become the defining pharmacology for certain subtypes of insect Ca(V) channels. This review focuses on peptidic spider toxins that specifically target insect Ca(V) channels. In addition to providing novel molecular tools for ion channel characterization, some of these toxins are being used as leads to develop new methods for controlling insect pests.

Amino Acid Sequence↗

High-Content CRISPR Screening: Methods and Applications.

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screening has become a central technology in functional genomics, enabling genome-scale interrogation via pooled perturbations. Early CRISPR screens employed survival or simple phenotypic readouts to identify essential genes and drug resistance mechanisms. However, as biological questions have shifted toward understanding regulatory networks, cellular heterogeneity, and context-dependent gene functions, there has been increasing demand for screening strategies capable of capturing complex cellular phenotypes beyond cell fitness. Recent advances in single-cell sequencing, high-content imaging, and spatial transcriptomics have expanded the resolution of CRISPR screening by enabling multidimensional phenotypic characterization following genetic perturbation. By integrating pooled perturbations with diverse readouts, these approaches systematically map targeted gene edits to transcriptional states, cellular phenotypes, and microenvironmental contexts. Meanwhile, innovations in library design, delivery, and computational pipelines have further improved the robustness and interpretability of high-content screening platforms. This review synthesizes the methodological evolution of CRISPR screening, emphasizing advances in perturbation strategies, delivery systems, and multimodal readouts. Representative applications spanning oncology, immunotherapy, developmental biology, neurobiology, and infectious diseases are delineated to demonstrate refined gene network annotations. Additionally, existing technical bottlenecks, such as scalability, cost constraints, and in vivo limitations, are critically assessed. Finally, future directions are proposed to facilitate the development of precise medicine.

CRISPR screening↗

Molecular, pharmacological and functional diversity of 5-HT receptors.

Serotonin (5-hydroxytryptamine, 5-HT) is probably unique among the monoamines in that its effects are subserved by as many as 13 distinct heptahelical, G-protein-coupled receptors (GPCRs) and one (presumably a family of) ligand-gated ion channel(s). These receptors are divided into seven distinct classes (5-HT(1) to 5-HT(7)) largely on the basis of their structural and operational characteristics. Whilst this degree of physical diversity clearly underscores the physiological importance of serotonin, evidence for an even greater degree of operational diversity continues to emerge. The challenge for modern 5-HT research has therefore been to define more precisely the properties of the systems that make this incredible diversity possible. Much progress in this regard has been made during the last decade with the realisation that serotonin is possibly the least conservative monoamine transmitter and the cloning of its many receptors. Coupled with the actions of an extremely avid and efficient reuptake system, this array of receptor subtypes provides almost limitless signalling capabilities to the extent that one might even question the need for other transmitter systems. However, the complexity of the system appears endless, since posttranslational modifications, such as alternate splicing and RNA editing, increase the number of proteins, oligomerisation and heteromerisation increase the number of complexes, and multiple G-protein suggest receptor trafficking, allowing phenotypic switching and crosstalk within and possibly between receptor families. Whether all these possibilities are used in vivo under physiological or pathological conditions remains to be firmly established, but in essence, such variety will keep the 5-HT community busy for quite some time. Those who may have predicted that molecular biology would largely simplify the life of pharmacologists have missed the point for 5-HT research in particular and, most probably, for many other transmitters. This chapter is an attempt to summarise very briefly 5-HT receptor diversity. The reward for unravelling this complex array of serotonin receptor--effector systems may be substantial, the ultimate prize being the development of important new drugs in a range of disease areas.

Adenylyl Cyclases↗

Structure of the smooth muscle myosin light-chain kinase calmodulin-binding domain peptide bound to calmodulin.

The interaction between the peptide corresponding to the calmodulin-binding domain of the smooth muscle myosin light-chain kinase and (Ca2+)4-calmodulin has been studied by multinuclear and multidimensional nuclear magnetic resonance methods. The study was facilitated by the use of 15N-labeled peptide in conjunction with 15N-edited and 15N-correlated 1H spectroscopy. The peptide forms a 1:1 complex with calcium-saturated calmodulin which is in slow exchange with free peptide. The 1H and 15N resonances of the bound have been assigned. An extensive set of structural constraints for the bound peptide has been assembled from the analysis of nuclear Overhauser effects and three-bond coupling constants. The backbone conformation of the bound peptide has been determined using these constraints by use of distance geometry and related computational methods. The backbone conformation of the peptide has been determined to high precision and is generally indicative of helical secondary structure. Nonhelical backbone conformations are seen in the middle and at the C-terminal end of the bound peptide. These studies provide the first direct confirmation of the amphiphilic helix model for the structure of peptides bound to calcium-saturated calmodulin.

Amino Acid Sequence↗

Guide RNAs of the recently isolated LEM125 strain of Leishmania tarentolae: an unexpected complexity.

Guide RNAs (gRNAs) are encoded both in the maxicircle and minicircle components of the mitochondrial DNA of trypanosomatid protozoa. These RNAs mediate the precise insertion and deletion of U residues in transcripts of the maxicircle DNA. We showed previously that the old UC laboratory strain of Leishmania tarentolae apparently lost more than 40 minicircle-encoded gRNAs that are present in the recently isolated LEM125 strain (Thiemann et al., EMBO J, 1994, 13:5689-5700]. We have further analyzed the population of minicircle-encoded gRNAs in the LEM125 strain. Sau3AI and MspI minicircle libraries were constructed and screened for novel gRNAs by negative colony hybridization. This search yielded 20 minicircles encoding new gRNAs that covered most of the remaining gaps in the editing cascades of the ND8, ND9, G4, and G5 genes, and in addition, more than 30 minicircles containing either unassigned or undetectable gRNA genes. We also completely sequenced 34 of the 45 minicircle sequence classes encoding previously identified gRNAs. A total of 19 pairs of redundant gRNAs, which are gRNAs of different sequences covering the same editing blocks, were identified. The gRNAs in each redundant pair generally had different relative abundances and different extents of mismatches with edited sequences. Alignments of the minicircles encoding redundant gRNAs yielded 59 to 93% matching nucleotides, suggesting an origin from duplication of ancestral minicircles and subsequent genetic drift. We propose a functional explanation for the existence of redundant gRNAs in this strain.

Amino Acid Sequence↗

Spectroscopic evidence for backbone desolvation of helical peptides by 2,2,2-trifluoroethanol: an isotope-edited FTIR study.

2,2,2-Trifluoroethanol (TFE) is widely used to induce helix formation in peptides and proteins, but the mechanism behind this effect is still poorly understood. Several recent papers have proposed that TFE acts by selectively desolvating the peptide backbone groups of the helix state. Infrared (IR) spectroscopy of the amide I band of polypeptides can be used to probe both secondary structure and backbone solvation, making this technique well suited for addressing the effect of TFE on polypeptide conformation. In this paper, we report the IR spectra as a function of TFE concentration for an alanine-rich peptide based on the repeat (AAKAA)(n)(). The IR spectra confirm that TFE desolvates the helical state of the peptide to a greater extent than the random coil state. Moreover, using a series of specifically (13)C-labeled peptides, the precise residues desolvated in the presence of TFE were identified. The residues most desolvated by TFE are the alanines located at position i - 4 in the sequence, where i is a lysine residue. This pattern of desolvation is consistent with molecular dynamics simulations which predict strong interactions between the lysine side chain at position n and the backbone carbonyl of the alanine at position i - 4. This is the first direct spectroscopic evidence of specific desolvation of helix backbone atoms in model alanine-rich peptides.

Amino Acid Sequence↗

Reliable component analysis of the Stanford-Binet: Fourth Edition for 2- to 6-year-olds.

Reliable component analysis (RCA) was conducted on the Stanford-Binet: Fourth Edition subtests for 2- to 6-year-olds using the standardization sample. Scores were derived through RCA to assess the Verbal Comprehension and Non-Verbal Reasoning factors suggested for children in this age range. The scores derived through RCA had greater discriminant validity than did equally weighted scores, whose high intercorrelations preclude effective discrimination or incremental validity. The difference scores derived through RCA were compared with equally weighted difference scores in terms of reliability and three types of standard error. Differences between RCA scores were more reliable than were equally weighted differences. The more reliable differences resulted in more precise confidence intervals and more powerful significance tests.

Child, Preschool↗

Database for a hearing conservation program.

We have developed a database and an analysis program (NoiseScan) for noise-induced hearing loss (NIHL). The exposure data are based on the evaluation of the noise immission level, which includes duration, frequency content, and the use of, and the attenuation performance of, hearing protectors. The input data can handle an unlimited number of exposure periods. If the noise exposure level is not known, the program lists noise levels of comparable work places, and thus provides an estimate of exposure. Confounding medical factors that may contribute to NIHL, such as elevated serum cholesterol level, hypertension, and extensive use of pain killers, are collected. Combined exposure to agents that clearly contribute to NIHL, such as hand-arm vibration, tobacco smoking, use of aminoglycosides and exposure to solvents are also assessed. An unlimited number of audiograms can be stored, and all the data can be completed and edited following collection. The program gives the predicted hearing loss according to the ISO 1999 model based on total exposure. At present, our NoiseScan program (under continuous development in an EU research program) is suitable for the data collection of various risk factors. It can be used to determine whether the hearing loss is occupational in origin and to estimate the efficiency of hearing conservation measures. NoiseScan also predicts the development of hearing loss in individuals in 5-year periods. The goal is to improve and validate the rules by which single and combined risk factors contribute to HIHL, thus leading to more precise prediction of individual hearing loss, and for the evaluation of success of the hearing conservation programs.

Audiometry↗

QSPR using MOLGEN-QSPR: the example of haloalkane boiling points.

MOLGEN-QSPR is a software newly developed for use in quantitative structure property relationships (QSPR) work. It allows to import, to manually edit, or to generate chemical structures, to detect duplicate structures, to import or to manually input property values, to calculate the values of a broad pool of molecular descriptors, to establish QSPR equations (models), and using such models to predict unknown property values. In connection with the molecule generator MOLGEN, MOLGEN-QSPR is able to predict property values for all compounds in a predetermined structure space (inverse QSPR). Some of the features of MOLGEN-QSPR are demonstrated on the example of haloalkane boiling points. The data basis used here is broader than in previous studies, and the models established are both more precise and simpler than those previously reported.

Journal Article↗

An algorithm for comparing RNA secondary structures and searching for similar substructures.

To access the functional informations carried by RNA molecules at the level of their secondary structure interactions, we propose a comparison method based on a tree edit algorithm which takes into account the tree structure of RNA foldings. Any secondary structure is translated into a tree involving all its elementary substructures; then a shorter condensed tree is built in which any unbranched helix interspersed with bulges and interior loops is taken as a single node. This method includes several parameters: a comparison matrix between structural units, gap penalties, and the scoring between nodes of the condensed trees. Their effects have been analysed using as a model a rapidly divergent domain of the large ribosomal RNA, for which structural variation during evolution is well known. This method allows one to recognize precisely, in large target molecules, definite substructures that present with the query molecules only a limited set of closely related secondary structure features; it is still efficient if intervening features, which can correspond to insertion/deletion of entire stem regions, separate such structural elements. When coupled with a hierarchical clustering algorithm, this method is suitable for classifying RNA molecules according to their secondary structure homologies.

Algorithms↗

Single-laboratory evaluation of EPA method 8080 for determination of chlorinated pesticides and polychlorinated biphenyls in hazardous wastes.

Method 8080, as published in the Second Edition of "Test Methods for Evaluating Solid Waste," EPA Manual SW-846, has been evaluated in a single-laboratory study. The Florisil procedure recommended in Method 8080 for sample cleanup does not separate organochlorine pesticides (OCPs) from the polychlorinated biphenyls (PCBs). Consequently, gas chromatographic analysis of OCPs on the packed column recommended in the method may result in false identifications or in no identifications at all when PCBs are present. Therefore, silica gel was substituted for Florisil, a capillary column was substituted for the packed column, and a sulfur cleanup procedure was incorporated in the method. The revised method was evaluated with samples spiked at 3 concentrations. Precision and accuracy indicate that the revised method can be reliably applied to the determination of OCPs and PCBs in liquid and solid matrixes. Detection limits for liquid matrixes range from 0.02 to 0.09 micrograms/L for OCPs and from 0.5 to 0.9 micrograms/L for PCBs. Detection limits for solid matrixes range from 1 to 6 micrograms/kg for OCPs and from 60 to 70 micrograms/kg for PCBs.

Chromatography, Gas↗

Rapid prototyping as a tool for diagnosis and treatment planning for maxillary canine impaction.

Treating an impacted maxillary canine requires identifying its exact position; this can pose a challenge to both orthodontists and oral surgeons. The purpose of this article is to present a new method for diagnosis and treatment planning of maxillary canine impaction by using computed tomography combined with rapid prototyping. Computed tomography image files of a patient with tooth 13 impaction were edited to produce, by means of rapid prototyping, an anatomic model of the maxillary teeth and a single attachment model that was later used to fabricate a metal attachment to be bonded to the impacted tooth. The dental model was used in the diagnosis and orthodontic treatment planning, and to communicate with the patient and his parents. The model showed the exact anatomical relationship between the impacted tooth and the other teeth; it was the main aid in intraoperative navigation during surgery to expose the tooth. The metal attachment built from the prototype was bonded to tooth 13 during surgery. Prototyping could become a new tool for fabricating brackets and other precision accessories for specific needs. Dental models made with rapid prototyping could become the diagnostic procedure of choice for evaluating impacted maxillary canines.

Adolescent↗

New aspects in the staging of lung cancer. Prospective validation of the International Union Against Cancer TNM classification.

BACKGROUND AND METHODS: To validate the new TNM definitions for lung cancer (International Union Against Cancer [UICC] TNM classification, 4th edition, 1987), the data of 3823 patients were analyzed prospectively in terms of concordance between clinical (TNM) and pathologically confirmed classification (pTNM), the value of the various diagnostic techniques in estimating the pathologically confirmed classification, and the prognostic relevance of the new TNM definitions. RESULTS: With regard to the primary tumor (T), clinical and pathologic classifications were identical in 63%; with regard to lymph node involvement (N), the agreement was 47%; for distant metastasis agreement occurred in 91% of cases and for the stages it occurred in 56%. As to the primary tumor (T), the accuracy of radiography (59%) was nearly identical to that of computed tomography (CT) (58%). Both techniques were less precise in determining the extent of lymph node involvement (CT, correct assessments in 50%; radiography, correct assessments in 43%). The statistically significant differences in the prognosis for the T, N, and M categories and for the stages and the categories of the new R classification could be confirmed. Allowance should be made for the different prognosis between T1N0M0 and T2N0M0 by the new Substages IA and Ib of Stage I. CONCLUSIONS: By the new TNM definitions for bronchus carcinoma, international conformity became feasible and practical, and the improvement of its prognostic relevance provided a more reliable basis for establishing guidelines for individual oncologic concepts.

Bronchial Neoplasms↗

An unattended device for sleep-related breathing disorders: validation study in suspected obstructive sleep apnoea syndrome.

Portable devices for the diagnosis of obstructive sleep apnoea (OSA) are considered to be an acceptable alternative to polysomnography (PSG), but their validation is essential. The aim of our study was to validate a device specifically designed for OSA diagnosis. Twenty nine suspected OSA patients were studied with simultaneous nocturnal PSG and an unattended recording device (MicroDigitrapper-S) (M-S). The device measured body position, snoring sound, oronasal flow, thoracic and abdominal effort, heart rate and percentage arterial oxygen saturation (Sa,O2%). We compared the apnoea plus hypopnoea index (AHI) and Sa,O2% results of PSG with that of the system's automatic analysis (M-SA). We also performed a semiautomatic analysis (M-SS) with visual editing of the raw data. Results at different AHI cut-off levels were analysed to obtain an indication of accuracy in diagnosis and severity. Both M-SA and M-SS showed a sensitivity and specificity of 100% at the cut-off level of AHI > 10. When increasing the cut-off levels, M-SA sensitivity decreased (55% for AHI > 40), while specificity remained high (95%). This was improved to a clinically acceptable level of agreement by M-SS analysis (sensitivity 91% and specificity 94%). In conclusion, the MicroDigitrapper-S device showed a good sensitivity and specificity for the diagnosis of OSA. However, the device could not predict the severity of OSA precisely enough. In severe cases (apnoea plus hypopnoea index > 40), semi-automatic scoring was necessary to obtain a more accurate detection of the severity of the disease.

Adult↗