Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 323
Filter
1.
Cureus ; 16(6): e61638, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38966482

ABSTRACT

BACKGROUND: The intertrochanteric fracture is a frequently occurring fracture, often attributed to osteoporosis in older populations. Recently, there has been a proposal to perform early surgical fixation on elderly patients to facilitate early rehabilitation. This approach has been shown to have a beneficial effect in lowering comorbidities. The study aims to compare the efficacy of the twin screw derotation type cephalomedullary nail with that of the single helical blade type cephalomedullary nail in the management of unstable intertrochanteric fractures. METHODOLOGY:  The research sample included patients from the orthopedic outpatient and emergency departments of Adesh Medical College and Hospital, Ambala Cantt, India, who were scheduled for surgery for unstable intertrochanteric femur fractures. The patients were categorized into two groups according to the kind of implant they were given: either a twin screw derotation cephalomedullary nail or a single helical blade cephalomedullary nail. The functional result was evaluated by comparing the modified Harris hip score (HHS). Patients with unstable intertrochanteric fractures, including reverse oblique fractures and fractures with posteromedial comminution, as well as patients who provided consent, were included in this study. RESULTS:  Thirteen individuals received treatment with proximal femoral nail antirotation (PFNA2), whereas 19 individuals received treatment with proximal femoral nail (PFN). The mean age in the PFNA2 group was 69.51, whereas the mean age in the PFN group was 70.804. There were three patients in the PFNA2 group and five patients in the PFN group who had a tip apex distance of more than 25 mm. According to the Cleveland index, nine patients in the PFNA2 group and eight patients in the PFN group had an implant location that was not optimum. Four patients in the PFNA2 group and seven patients in the PFN group had a neck shaft angle difference of more than 10° between their undamaged and operated sides. The mean HHS was 74.55 for the PFNA2 group and 69.88 for the PFN group. The PFNA2 group exhibited four problems, whereas the PFN group had five issues. CONCLUSION:  The study found that both implants offer similar functional outcomes, with adherence to specific radiological parameters optimizing results. While both face similar challenges with osteoporosis, there was no notable distinction between them. Notably, the PFNA2 group showed superior outcomes in perioperative morbidity.

2.
FEBS J ; 2024 Jun 29.
Article in English | MEDLINE | ID: mdl-38944686

ABSTRACT

Within the three-dimensional (3D) nuclear space, the genome organizes into a series of orderly structures that impose important influences on gene regulation. T lymphocytes, crucial players in adaptive immune responses, undergo intricate transcriptional remodeling upon activation, leading to differentiation into specific effector and memory T cell subsets. Recent evidence suggests that T cell activation is accompanied by dynamic changes in genome architecture at multiple levels, providing a unique biological context to explore the functional relevance and molecular mechanisms of 3D genome organization. Here, we summarize recent advances that link the reorganization of genome architecture to the remodeling of transcriptional programs and conversion of cell fates during T cell activation and differentiation. We further discuss how various chromatin architecture regulators, including CCCTC-binding factor and several transcription factors, collectively modulate the genome architecture during this process.

3.
Genes Dev ; 38(9-10): 436-454, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38866556

ABSTRACT

Genome organization can regulate gene expression and promote cell fate transitions. The differentiation of germline stem cells (GSCs) to oocytes in Drosophila involves changes in genome organization mediated by heterochromatin and the nuclear pore complex (NPC). Heterochromatin represses germ cell genes during differentiation, and NPCs anchor these silenced genes to the nuclear periphery, maintaining silencing to allow for oocyte development. Surprisingly, we found that genome organization also contributes to NPC formation, mediated by the transcription factor Stonewall (Stwl). As GSCs differentiate, Stwl accumulates at boundaries between silenced and active gene compartments. Stwl at these boundaries plays a pivotal role in transitioning germ cell genes into a silenced state and activating a group of oocyte genes and nucleoporins (Nups). The upregulation of these Nups during differentiation is crucial for NPC formation and further genome organization. Thus, cross-talk between genome architecture and NPCs is essential for successful cell fate transitions.


Subject(s)
Cell Differentiation , Drosophila Proteins , Genome, Insect , Nuclear Pore , Oogenesis , Animals , Oogenesis/genetics , Drosophila Proteins/metabolism , Drosophila Proteins/genetics , Cell Differentiation/genetics , Nuclear Pore/metabolism , Nuclear Pore/genetics , Genome, Insect/genetics , Gene Expression Regulation, Developmental/genetics , Female , Drosophila melanogaster/genetics , Oocytes/metabolism , Transcription Factors/metabolism , Transcription Factors/genetics , Drosophila/genetics , Nuclear Pore Complex Proteins/metabolism , Nuclear Pore Complex Proteins/genetics
4.
bioRxiv ; 2024 May 24.
Article in English | MEDLINE | ID: mdl-38826443

ABSTRACT

Mechanisms of X chromosome dosage compensation have been studied extensively in a few model species representing clades of shared sex chromosome ancestry. However, the diversity within each clade as a function of sex chromosome evolution is largely unknown. Here, we anchor ourselves to the nematode Caenorhabditis elegans, for which a well-studied mechanism of dosage compensation occurs through a specialized structural maintenance of chromosomes (SMC) complex, and explore the diversity of dosage compensation in the surrounding phylogeny of nematodes. Through phylogenetic analysis of the C. elegans dosage compensation complex and a survey of its epigenetic signatures, including X-specific topologically associating domains (TADs) and X-enrichment of H4K20me1, we found that the condensin-mediated mechanism evolved recently in the lineage leading to Caenorhabditis through an SMC-4 duplication. Intriguingly, an independent duplication of SMC-4 and the presence of X-specific TADs in Pristionchus pacificus suggest that condensin-mediated dosage compensation arose more than once. mRNA-seq analyses of gene expression in several nematode species indicate that dosage compensation itself is ancestral, as expected from the ancient XO sex determination system. Indicative of the ancestral mechanism, H4K20me1 is enriched on the X chromosomes in Oscheius tipulae, which does not contain X-specific TADs or SMC-4 paralogs. Together, our results indicate that the dosage compensation system in C. elegans is surprisingly new, and condensin may have been co-opted repeatedly in nematodes, suggesting that the process of evolving a chromosome-wide gene regulatory mechanism for dosage compensation is constrained. Significance statement: X chromosome dosage compensation mechanisms evolved in response to Y chromosome degeneration during sex chromosome evolution. However, establishment of dosage compensation is not an endpoint. As sex chromosomes change, dosage compensation strategies may have also changed. In this study, we performed phylogenetic and epigenomic analyses surrounding Caenorhabditis elegans and found that the condensin-mediated dosage compensation mechanism in C. elegans is surprisingly new, and has evolved in the presence of an ancestral mechanism. Intriguingly, condensin-based dosage compensation may have evolved more than once in the nematode lineage, the other time in Pristionchus. Together, our work highlights a previously unappreciated diversity of dosage compensation mechanisms within a clade, and suggests constraints in evolving new mechanisms in the presence of an existing one.

5.
Stress Biol ; 4(1): 30, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38864932

ABSTRACT

Although genome-wide A-to-I editing mediated by adenosine-deaminase-acting-on-tRNA (ADAT) occurs during sexual reproduction in the presence of stage-specific cofactors, RNA editing is not known to occur during vegetative growth in filamentous fungi. Here we identified 33 A-to-I RNA editing events in vegetative hyphae of Fusarium graminearum and functionally characterized one conserved hyphal-editing site. Similar to ADAT-mediated editing during sexual reproduction, majority of hyphal-editing sites are in coding sequences and nonsynonymous, and have strong preference for U at -1 position and hairpin loops. Editing at TA437G, one of the hyphal-specific editing sites, is a premature stop codon correction (PSC) event that enables CHE1 gene to encode a full-length zinc fingertranscription factor. Manual annotations showed that this PSC site is conserved in CHE1 orthologs from closely-related Fusarium species. Whereas the che1 deletion and CHE1TAA (G438 to A) mutants had no detectable phenotype, the CHE1TGG (A437 to G) mutant was defective in hyphal growth, conidiation, sexual reproduction, and plant infection. However, the CHE1TGG mutant was increased in tolerance against oxidative stress and editing of TA437G in CHE1 was stimulated by H2O2 treatment in F. graminearum. These results indicate that fixation of the premature stop codon in CHE1 has a fitness cost on normal hyphal growth and reproduction but provides a benefit to tolerance against oxidative stress. Taken together, A-to-I editing events, although rare (not genome-wide), occur during vegetative growth and editing in CHE1 plays a role in response to oxidative stress in F. graminearum and likely in other fungal pathogens.

6.
Brief Bioinform ; 25(4)2024 May 23.
Article in English | MEDLINE | ID: mdl-38935071

ABSTRACT

Advances in chromatin mapping have exposed the complex chromatin hierarchical organization in mammals, including topologically associating domains (TADs) and their substructures, yet the functional implications of this hierarchy in gene regulation and disease progression are not fully elucidated. Our study delves into the phenomenon of shared TAD boundaries, which are pivotal in maintaining the hierarchical chromatin structure and regulating gene activity. By integrating high-resolution Hi-C data, chromatin accessibility, and DNA double-strand breaks (DSBs) data from various cell lines, we systematically explore the complex regulatory landscape at high-level TAD boundaries. Our findings indicate that these boundaries are not only key architectural elements but also vibrant hubs, enriched with functionally crucial genes and complex transcription factor binding site-clustered regions. Moreover, they exhibit a pronounced enrichment of DSBs, suggesting a nuanced interplay between transcriptional regulation and genomic stability. Our research provides novel insights into the intricate relationship between the 3D genome structure, gene regulation, and DNA repair mechanisms, highlighting the role of shared TAD boundaries in maintaining genomic integrity and resilience against perturbations. The implications of our findings extend to understanding the complexities of genomic diseases and open new avenues for therapeutic interventions targeting the structural and functional integrity of TAD boundaries.


Subject(s)
Chromatin , DNA Breaks, Double-Stranded , DNA Repair , Gene Expression Regulation , Humans , Chromatin/metabolism , Chromatin/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Animals , Genomics/methods , Genomic Instability , Chromatin Assembly and Disassembly
7.
BMC Public Health ; 24(1): 1364, 2024 May 21.
Article in English | MEDLINE | ID: mdl-38773444

ABSTRACT

OBJECTIVE: Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) are considered gold standards for measuring visceral fat area (VFA). However, their relatively high prices and potential radiation exposure limit their widespread use in clinical practice and everyday life. Therefore, our study aims to develop a VFA estimated equation based on sagittal abdominal diameter (SAD) and transverse abdominal diameter (TAD) using anthropometric indexes. To the best of our knowledge, there have been limited studies investigating this aspect thus far. METHODS: This study was designed as a cross-sectional, retrospective cohort survey. A total of 288 patients (167 males and 121 females) aged 18-80 with type 2 diabetes (T2D) were consecutively collected from a multicenter hospital, and VFA was measured by CT. Subsequently, variables highly correlated with VFA were screened through general linear correlation analysis. A stepwise regression analysis was then conducted to develop a VFA estimated equation. Discrepancies between the estimated and actual VFA values were assessed using the Bland-Altman method to validate the accuracy of the equation. RESULTS: In the female T2D population, triglyceride (TG), SAD, TAD were found to be independently correlated with VFA; in the male T2D population, BMI, TG, SAD and TAD showed independent correlations with VFA. Among these variables, SAD exhibited the strongest correlation with VFA (r = 0.83 for females, r = 0.88 for males), followed by TAD (r = 0.69 for females, r = 0.79 for males). Based on these findings, a VFA estimated equation was developed for the T2D population: VFA (male) =-364.16 + 15.36*SAD + 0.77*TG + 9.41*TAD - 5.00*BMI (R2 = 0.75, adjusted R2 = 0.74); VFA(female)=-170.87 + 9.72*SAD-24.29*(TG^-1) + 3.93*TAD (R2 = 0.69, adjusted R2 = 0.68). Both models demonstrated a good fit. The Bland-Altman plot indicated a strong agreement between the actual VFA values and the estimated values, the mean differences were close to 0, and the majority of differences fell within the 95% confidence interval. CONCLUSIONS: In the T2D population, a VFA estimated equation is developed by incorporating SAD and TAD along with other measurement indices. This equation demonstrates a favorable estimated performance, suggesting to the development of novel and practical VFA estimation models in the future study.


Subject(s)
Diabetes Mellitus, Type 2 , Intra-Abdominal Fat , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Cross-Sectional Studies , Intra-Abdominal Fat/diagnostic imaging , Retrospective Studies , Sagittal Abdominal Diameter , Tomography, X-Ray Computed
8.
Epigenetics Chromatin ; 17(1): 13, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38705995

ABSTRACT

BACKGROUND: Multiple studies have demonstrated a negative correlation between gene expression and positioning of genes at the nuclear envelope (NE) lined by nuclear lamina, but the exact relationship remains unclear, especially in light of the highly stochastic, transient nature of the gene association with the NE. RESULTS: In this paper, we ask whether there is a causal, systematic, genome-wide relationship between the expression levels of the groups of genes in topologically associating domains (TADs) of Drosophila nuclei and the probabilities of TADs to be found at the NE. To investigate the nature of this possible relationship, we combine a coarse-grained dynamic model of the entire Drosophila nucleus with genome-wide gene expression data; we analyze the TAD averaged transcription levels of genes against the probabilities of individual TADs to be in contact with the NE in the control and lamins-depleted nuclei. Our findings demonstrate that, within the statistical error margin, the stochastic positioning of Drosophila melanogaster TADs at the NE does not, by itself, systematically affect the mean level of gene expression in these TADs, while the expected negative correlation is confirmed. The correlation is weak and disappears completely for TADs not containing lamina-associated domains (LADs) or TADs containing LADs, considered separately. Verifiable hypotheses regarding the underlying mechanism for the presence of the correlation without causality are discussed. These include the possibility that the epigenetic marks and affinity to the NE of a TAD are determined by various non-mutually exclusive mechanisms and remain relatively stable during interphase. CONCLUSIONS: At the level of TADs, the probability of chromatin being in contact with the nuclear envelope has no systematic, causal effect on the transcription level in Drosophila. The conclusion is reached by combining model-derived time-evolution of TAD locations within the nucleus with their experimental gene expression levels.


Subject(s)
Chromatin , Drosophila melanogaster , Nuclear Lamina , Transcription, Genetic , Animals , Nuclear Lamina/metabolism , Drosophila melanogaster/metabolism , Chromatin/metabolism
9.
BMC Biol ; 22(1): 114, 2024 May 20.
Article in English | MEDLINE | ID: mdl-38764013

ABSTRACT

BACKGROUND: Cotton is a major world cash crop and an important source of natural fiber, oil, and protein. Drought stress is becoming a restrictive factor affecting cotton production. To facilitate the development of drought-tolerant cotton varieties, it is necessary to study the molecular mechanism of drought stress response by exploring key drought-resistant genes and related regulatory factors. RESULTS: In this study, two cotton varieties, ZY007 (drought-sensitive) and ZY168 (drought-tolerant), showing obvious phenotypic differences under drought stress, were selected. A total of 25,898 drought-induced genes were identified, exhibiting significant enrichment in pathways related to plant stress responses. Under drought induction, At subgenome expression bias was observed at the whole-genome level, which may be due to stronger inhibition of Dt subgenome expression. A gene co-expression module that was significantly associated with drought resistance was identified. About 90% of topologically associating domain (TAD) boundaries were stable, and 6613 TAD variation events were identified between the two varieties under drought. We identified 92 genes in ZY007 and 98 in ZY168 related to chromatin 3D structural variation and induced by drought stress. These genes are closely linked to the cotton response to drought stress through canonical hormone-responsive pathways, modulation of kinase and phosphatase activities, facilitation of calcium ion transport, and other related molecular mechanisms. CONCLUSIONS: These results lay a foundation for elucidating the molecular mechanism of the cotton drought response and provide important regulatory locus and gene resources for the future molecular breeding of drought-resistant cotton varieties.


Subject(s)
Chromatin , Droughts , Gene Expression Regulation, Plant , Gossypium , Gossypium/genetics , Gossypium/physiology , Chromatin/metabolism , Stress, Physiological/genetics , Genes, Plant
10.
Clin Transl Med ; 14(5): e1682, 2024 May.
Article in English | MEDLINE | ID: mdl-38769659

ABSTRACT

BACKGROUND: The three-dimensional (3D) genome architecture plays a critical role inregulating gene expression. However, the specific alterations in thisarchitecture within somatotroph tumors and their implications for gene expression remain largely unexplored. METHODS: We employed Hi-C and RNA-seq analyses to compare the 3D genomic structures of somatotroph tumors with normal pituitary tissue. This comprehensive approachenabled the characterization of A/B compartments, topologically associateddomains (TADs), and chromatin loops, integrating these with gene expression patterns. RESULTS: We observed a decrease in both the frequency of chromosomal interactions andthe size of TADs in tumor tissue compared to normal tissue. Conversely, the number of TADs and chromatin loops was found to be increased in tumors. Integrated analysis of Hi-C and RNA-seq data demonstrated that changes inhigher-order chromat in structure were associated with alterations in gene expression. Specifically, genes in A compartments showed higher density and increased expression relative to those in B compartments. Moreover, the weakand enhanced insulation boundaries were identified, and the associated genes were enriched in the Wnt/ß-Catenin signaling pathway. We identified the gainedand lost loops in tumor and integrated these differences with transcriptional changes to examine the functional relevance of the identified loops. Notably, we observed an enhanced insulation boundary and a greater number of loops in the TCF7L2 gene region within tumors, which was accompanied by an upregulation of TCF7L2 expression. Subsequently, TCF7L2 expression was confirmed through qRT-PCR, and upregulated TCF7L2 prompted cell proliferation and growth hormone (GH) secretion in vitro. CONCLUSION: Our results provide comprehensive 3D chromatin architecture maps of somatotroph tumors and offer a valuable resource for furthering the understanding of the underlying biology and mechanisms of gene expression regulation.


Subject(s)
Chromatin , Humans , Chromatin/genetics , Chromatin/metabolism , Pituitary Neoplasms/genetics , Pituitary Neoplasms/pathology , Pituitary Neoplasms/metabolism , Somatotrophs/metabolism , Somatotrophs/pathology
11.
Forensic Sci Int Genet ; 71: 103051, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38670007

ABSTRACT

PURPOSE: Thoracic aortic dissection (TAD) is a life-threatening cardiovascular disease that often results in sudden cardiac death (SCD). However, the genetic characteristics of individuals with TAD confirmed at autopsy have been rarely studied. Our objective was to determine the prevalence of pathogenic variants in TAD-associated genes in a cohort of sporadic deaths resulting from spontaneous rupture of TAD and identify relevant genotype-phenotype relationships in Han Chinese population. METHODS: We included sixty-one consecutive sporadic decedents whose primary cause of death was spontaneous rupture of TAD, and performed a whole exome sequencing based strategy comprising 26 known TAD-associated genes. RESULTS: We identified 7 pathogenic or likely pathogenic (P/LP) variants in 7 cases (11.48 %) and 22 variants of uncertain significance (VUS) in 22 cases (36.07 %). The FBN1 gene was found to be the major disease-causing gene. Notably, TAD decedents with P/LP variant exhibited significantly earlier mortality. Moreover, we reported for the first time that TAD decedents with P/LP variant had a shorter diagnosis and treatment time. CONCLUSION: Our study investigated the genetic characteristics of TAD individuals confirmed until autopsy in Han Chinese population. The findings enhanced the understanding of the genetic underpinnings of TAD and have significant implications for clinical management and forensic investigations.


Subject(s)
Aortic Aneurysm, Thoracic , Aortic Dissection , Exome Sequencing , Adult , Aged , Female , Humans , Male , Middle Aged , Adipokines , Aortic Aneurysm, Thoracic/genetics , Aortic Aneurysm, Thoracic/mortality , Aortic Dissection/genetics , Aortic Dissection/mortality , Aortic Rupture/genetics , China , Cohort Studies , Dissection, Thoracic Aorta , East Asian People/genetics , Fibrillin-1/genetics , Rupture, Spontaneous/genetics
12.
Ann Surg Oncol ; 31(7): 4477-4486, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38523225

ABSTRACT

BACKGROUND: The targeted axillary dissection (TAD) procedure is used in clinically positive lymph node (cN+) breast cancer to assess whether pathological complete response (pCR) is achieved after neoadjuvant systemic therapy (NST) to decide on de-escalation of axillary lymph node dissection (ALND). In this study, we review the implementation of the TAD procedure in a large regional breast cancer center. METHODS: All TAD procedures between 2016 and 2022 were reviewed. The TAD procedure consists of marking pre-NST the largest suspected metastatic lymph node(s) using a radioactive I-125 seed. During surgery, the marked node was excised together with a sentinel node procedure. Axillary therapy (ALND, axillary radiotherapy, or nothing) recommendations were based on the amount of suspected positive axillary lymph nodes (ALNs < 4 or ≥ 4) pre-NST and if pCR was achieved after NST. RESULTS: A total of 312 TAD procedures were successfully performed in 309 patients. In 134 (43%) cases, pCR of the TAD lymph nodes were achieved. Per treatment protocol, 43 cases (14%) did not receive any axillary treatment, 218 cases (70%) received adjuvant axillary radiotherapy, and 51 cases (16%) underwent an ALND. During a median follow-up of 2.8 years, 46 patients (14%) developed recurrence, of which 11 patients (3.5%) had axillary recurrence. CONCLUSIONS: Introduction of the TAD procedure has resulted in a reduction of 84% of previously indicated ALNDs. Moreover, 18% of cases did not receive adjuvant axillary radiotherapy. These data show that implementation of de-escalation axillary treatment with the TAD procedure appeared to be successful.


Subject(s)
Axilla , Breast Neoplasms , Lymph Node Excision , Humans , Breast Neoplasms/pathology , Breast Neoplasms/surgery , Female , Lymph Node Excision/methods , Retrospective Studies , Middle Aged , Adult , Aged , Follow-Up Studies , Lymphatic Metastasis , Neoadjuvant Therapy , Sentinel Lymph Node Biopsy/methods , Lymph Nodes/pathology , Lymph Nodes/surgery , Prognosis , Aged, 80 and over , Radiotherapy, Adjuvant , Carcinoma, Ductal, Breast/surgery , Carcinoma, Ductal, Breast/pathology
13.
Elife ; 122024 Mar 19.
Article in English | MEDLINE | ID: mdl-38502563

ABSTRACT

Compartment formation in interphase chromosomes is a result of spatial segregation between euchromatin and heterochromatin on a few megabase pairs (Mbp) scale. On the sub-Mbp scales, topologically associating domains (TADs) appear as interacting domains along the diagonal in the ensemble averaged Hi-C contact map. Hi-C experiments showed that most of the TADs vanish upon deleting cohesin, while the compartment structure is maintained, and perhaps even enhanced. However, closer inspection of the data reveals that a non-negligible fraction of TADs is preserved (P-TADs) after cohesin loss. Imaging experiments show that, at the single-cell level, TAD-like structures are present even without cohesin. To provide a structural basis for these findings, we first used polymer simulations to show that certain TADs with epigenetic switches across their boundaries survive after depletion of loops. More importantly, the three-dimensional structures show that many of the P-TADs have sharp physical boundaries. Informed by the simulations, we analyzed the Hi-C maps (with and without cohesin) in mouse liver and human colorectal carcinoma cell lines, which affirmed that epigenetic switches and physical boundaries (calculated using the predicted 3D structures using the data-driven HIPPS method that uses Hi-C as the input) explain the origin of the P-TADs. Single-cell structures display TAD-like features in the absence of cohesin that are remarkably similar to the findings in imaging experiments. Some P-TADs, with physical boundaries, are relevant to the retention of enhancer-promoter/promoter-promoter interactions. Overall, our study shows that preservation of a subset of TADs upon removing cohesin is a robust phenomenon that is valid across multiple cell lines.


Subject(s)
Chromatin , Cohesins , Animals , Mice , Humans , Chromosomes , Heterochromatin , Interphase
14.
Materials (Basel) ; 17(6)2024 Mar 10.
Article in English | MEDLINE | ID: mdl-38541434

ABSTRACT

This study utilizes desalted and denitrated treated aluminum dross (TAD) as a raw material, along with kaolin and 10 ppi (pores per inch) polyurethane foam as a template. The slurry is converted into an aluminum dross green body with a three-dimensional network structure using the impregnation method. A three-dimensional network aluminum dross ceramic framework (TAD3D) is created at a sintering temperature of 1350 °C. The liquid 5A05 aluminum alloy at a temperature of 950 °C infiltrates into the voids of TAD3D through pressureless infiltration, resulting in TAD3D/5A05Al composite material with an interpenetrating phase composite (IPC) structure. The corrosion behavior of TAD3D/5A05 composite material in sodium chloride solution was examined using the salt spray test (NSS) method. The study shows that the pores of the TAD3D framework, produced by sintering aluminum dross as raw material, are approximately 10 ppi. The bonding between TAD3D and 5A05Al interfaces is dense, with strong interfacial adhesion. The NSS corrosion time ranged from 24 h to 360 h, during which the composite material underwent pitting corrosion, crevice corrosion and self-healing processes. Results from Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) indicate that, as corrosion progresses, the Ecorr of TAD3D/5A05Al decreases from -0.718 V to -0.786 V, and Icorr decreases from 0.398 µA·cm-2 to 0.141 µA·cm-2. A dense oxide film forms on the surface of the composite material, increasing the anodic Tafel slope and decreasing the cathodic Tafel slope, thus slowing down the rates of cathodic and anodic reactions. Factors such as lower interface corrosion resistance or a relatively weak passivation film at the interface do not significantly diminish the corrosion resistance of TAD3D and 5A05Al. The corrosion resistance of the composite material initially decreases and then increases.

15.
Plants (Basel) ; 13(5)2024 Feb 25.
Article in English | MEDLINE | ID: mdl-38475474

ABSTRACT

Type IVc Pili (T4cP), also known as Tad or Flp pili, are long thin microbial filaments that are made up of small-sized pilins. These appendages serve different functions in bacteria, including attachment, biofilm formation, surface sensing, motility, and host colonization. Despite their relevant role in diverse microbial lifestyles, knowledge about T4cP in bacteria that establish symbiosis with legumes, collectively referred to as rhizobia, is still limited. Sinorhizobium meliloti contains two clusters of T4cP-related genes: flp-1 and flp-2, which are located on the chromosome and the pSymA megaplasmid, respectively. Bundle-forming pili associated with flp-1 are involved in the competitive nodulation of alfalfa plants, but the role of flp-2 remains elusive. In this work, we have performed a comprehensive bioinformatic analysis of T4cP genes in the highly competitive S. meliloti GR4 strain and investigated the role of its flp clusters in pilus biogenesis, motility, and in the interaction with alfalfa. Single and double flp-cluster mutants were constructed on the wild-type genetic background as well as in a flagellaless derivative strain. Our data demonstrate that both chromosomal and pSymA flp clusters are functional in pili biogenesis and contribute to surface translocation and nodule formation efficiency in GR4. In this strain, the presence of flp-1 in the absence of flp-2 reduces the competitiveness for nodule occupation.

16.
Front Endocrinol (Lausanne) ; 15: 1345363, 2024.
Article in English | MEDLINE | ID: mdl-38481440

ABSTRACT

X-linked acrogigantism (X-LAG) is a rare form of pituitary gigantism that is associated with growth hormone (GH) and prolactin-secreting pituitary adenomas/pituitary neuroendocrine tumors (PitNETs) that develop in infancy. It is caused by a duplication on chromosome Xq26.3 that leads to the misexpression of the gene GPR101, a constitutively active stimulator of pituitary GH and prolactin secretion. GPR101 normally exists within its own topologically associating domain (TAD) and is insulated from surrounding regulatory elements. X-LAG is a TADopathy in which the duplication disrupts a conserved TAD border, leading to a neo-TAD in which ectopic enhancers drive GPR101 over-expression, thus causing gigantism. Here we trace the full diagnostic and therapeutic pathway of a female patient with X-LAG from 4C-seq studies demonstrating the neo-TAD through medical and surgical interventions and detailed tumor histopathology. The complex nature of treating young children with X-LAG is illustrated, including the achievement of hormonal control using a combination of neurosurgery and adult doses of first-generation somatostatin analogs.


Subject(s)
Acromegaly , Genetic Diseases, X-Linked , Gigantism , Human Growth Hormone , Pituitary Neoplasms , Adult , Humans , Child , Female , Child, Preschool , Gigantism/genetics , Gigantism/therapy , Gigantism/metabolism , Acromegaly/pathology , Growth Hormone/metabolism , Genetic Diseases, X-Linked/genetics , Genetic Diseases, X-Linked/therapy , Pituitary Neoplasms/complications , Pituitary Neoplasms/genetics , Pituitary Neoplasms/pathology
17.
SICOT J ; 10: 9, 2024.
Article in English | MEDLINE | ID: mdl-38415767

ABSTRACT

INTRODUCTION: Lateral fractures of proximal femur are the most frequent fractures in elderly people. Internal fixation using medullary nails is the gold standard of treatment (Gamma 3 nail is the most implanted device) due to reduced incidence of complications than other devices. We report our experience in treating this kind of fractures with Gamma 3 nail, between January 2015 and December 2021. METHODS: We performed a retrospective cohort study of patients treated in our orthopaedic department; level of clinical care is III: 559 patients (431 females and 128 males, with an average age of 85.3 years) with lateral femoral neck fracture. All patients were surgically treated with Gamma 3 standard nail (SGN). We evaluated preliminary X-rays to classify fractures, according to AO-OTA classification and post-operative X-ray to verify cephalic screw position site, according to areas described by Cleveland in 1959: we measured tip-to-apex distance (TAD) and tip-to-apex calcar referred distance (CalTAD). Finally Chang reduction quality criteria (CRQC) for fracture reduction of trochanteric fractures were determined using preoperative or postoperative Antero-Posterior (AP) and lateral radiographs in a Picture Archiving and Communication System (PACS). Incidence of cut-out was evaluated in relation with these parameters. Patients were divided into 2 groups: first group had cephalic screw in optimal positions (5-8-9), the other group had cephalic screw in other positions. RESULTS: In 328 patients (58.7%) screw was in positions 5-8-9, in 231 patients (41.2%) screw was in not-optimal position. Median TAD was 19.1 ± 7.0 mm (range = 0.0-50.5); in 463 patients (82.8%) TAD was ≤ 25 mm. Median CalTAD was 21.4 ± 4.7 mm (range = 5.7-39.2); in 105 patients (79.4%) CalTAD was ≤ 25 mm. Cut-out was observed in 8 cases (1.43%). Multivariate analysis showed a significant correlation (p < 0,05) between incidence of cut-out and fracture type 31A2 and with TAD values >25 mm. Cephalic screw position did not influence incidence of cut-out. DISCUSSION: In order to obtain fracture healing with a low risk of failure, in particular cut-out, it is necessary to obtain good reduction of fracture and optimal lag screw position in order to achieve a TAD inferior to 25 mm.

18.
Microorganisms ; 12(1)2024 Jan 17.
Article in English | MEDLINE | ID: mdl-38258011

ABSTRACT

The Vibrio genus includes bacteria widely distributed in aquatic habitats and the infections caused by these bacteria can affect a wide range of hosts. They are able to adhere to numerous surfaces, which can result in biofilm formation that helps maintain them in the environment. The involvement of the biofilm lifestyle in the virulence of Vibrio pathogens of aquatic organisms remains to be investigated. Vibrio harveyi ORM4 is a pathogen responsible for an outbreak in European abalone Haliotis tuberculata populations. In the present study, we used a dynamic biofilm culture technique coupled with laser scanning microscopy to characterize the biofilm formed by V. harveyi ORM4. We furthermore used RNA-seq analysis to examine the global changes in gene expression in biofilm cells compared to planktonic bacteria, and to identify biofilm- and virulence-related genes showing altered expression. A total of 1565 genes were differentially expressed, including genes associated with motility, polysaccharide synthesis, and quorum sensing. The up-regulation of 18 genes associated with the synthesis of the type III secretion system suggests that this virulence factor is induced in V. harveyi ORM4 biofilms, providing indirect evidence of a relationship between biofilm and virulence.

19.
Cell Rep ; 43(1): 113663, 2024 01 23.
Article in English | MEDLINE | ID: mdl-38206813

ABSTRACT

The transcription factor ZNF143 contains a central domain of seven zinc fingers in a tandem array and is involved in 3D genome construction. However, the mechanism by which ZNF143 functions in chromatin looping remains unclear. Here, we show that ZNF143 directionally recognizes a diverse range of genomic sites directly within enhancers and promoters and is required for chromatin looping between these sites. In addition, ZNF143 is located between CTCF and cohesin at numerous CTCF sites, and ZNF143 removal narrows the space between CTCF and cohesin. Moreover, genetic deletion of ZNF143, in conjunction with acute CTCF degradation, reveals that ZNF143 and CTCF collaborate to regulate higher-order topological chromatin organization. Finally, CTCF depletion enlarges direct ZNF143 chromatin looping. Thus, ZNF143 is recruited by CTCF to the CTCF sites to regulate CTCF/cohesin configuration and TAD (topologically associating domain) formation, whereas directional recognition of genomic DNA motifs directly by ZNF143 itself regulates promoter activity via chromatin looping.


Subject(s)
Chromosomal Proteins, Non-Histone , Cohesins , Chromosomal Proteins, Non-Histone/metabolism , CCCTC-Binding Factor/metabolism , Chromatin , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Binding Sites
20.
Cell Genom ; 4(2): 100488, 2024 Feb 14.
Article in English | MEDLINE | ID: mdl-38280381

ABSTRACT

Whole-genome sequencing (WGS) studies of autism spectrum disorder (ASD) have demonstrated the roles of rare promoter de novo variants (DNVs). However, most promoter DNVs in ASD are not located immediately upstream of known ASD genes. In this study analyzing WGS data of 5,044 ASD probands, 4,095 unaffected siblings, and their parents, we show that promoter DNVs within topologically associating domains (TADs) containing ASD genes are significantly and specifically associated with ASD. An analysis considering TADs as functional units identified specific TADs enriched for promoter DNVs in ASD and indicated that common variants in these regions also confer ASD heritability. Experimental validation using human induced pluripotent stem cells (iPSCs) showed that likely deleterious promoter DNVs in ASD can influence multiple genes within the same TAD, resulting in overall dysregulation of ASD-associated genes. These results highlight the importance of TADs and gene-regulatory mechanisms in better understanding the genetic architecture of ASD.


Subject(s)
Autism Spectrum Disorder , Induced Pluripotent Stem Cells , Humans , Autism Spectrum Disorder/genetics , Genetic Predisposition to Disease/genetics , Gene Expression Regulation , Whole Genome Sequencing
SELECTION OF CITATIONS
SEARCH DETAIL
...