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Abstract Richter’s syndrome (RS) is the transformation of chronic lymphocytic leukemia (CLL) into a high-grade B-cell malignancy. Molecular and functional studies have pointed out that CLL cells are close to the apoptotic threshold and dependent on BCL-2 for survival. However, it remains undefined how evasion from apoptosis evolves during disease transformation. Here, we employed functional and static approaches to compare the regulation of mitochondrial apoptosis in CLL and RS. BH3 profiling of 17 CLL and 9 RS samples demonstrated that RS cells had reduced apoptotic priming and lower BCL-2 dependence than CLL cells. While a subset of RS was dependent on alternative anti-apoptotic proteins and was sensitive to specific BH3 mimetics, other RS cases harbored no specific anti-apoptotic addiction. Transcriptomics of paired CLL/RS samples revealed downregulation of pro-apoptotic sensitizers during disease transformation. Albeit expressed, effector and activator members were less likely to colocalize with mitochondria in RS compared to CLL. Electron microscopy highlighted reduced cristae width in RS mitochondria, a condition further promoting apoptosis resistance. Collectively, our data suggest that RS cells evolve multiple mechanisms that lower the apoptotic priming and shift the anti-apoptotic dependencies away from BCL-2, making direct targeting of mitochondrial apoptosis more challenging after disease transformation.

Summary: Response to multiple microenvironmental cues and resilience to mechanical stress are essential features of trafficking leukocytes. Here, we describe unexpected role of titin (TTN), the largest protein encoded by the human genome, in the regulation of mechanisms of lymphocyte trafficking. Human T and B lymphocytes express five TTN isoforms, exhibiting cell-specific expression, distinct localization to plasma membrane microdomains, and different distribution to cytosolic versus nuclear compartments. In T lymphocytes, the LTTN1 isoform governs the morphogenesis of plasma membrane microvilli independently of ERM protein phosphorylation status, thus allowing selectin-mediated capturing and rolling adhesions. Likewise, LTTN1 controls chemokine-triggered integrin activation. Accordingly, LTTN1 mediates rho and rap small GTPases activation, but not actin polymerization. In contrast, chemotaxis is facilitated by LTTN1 degradation. Finally, LTTN1 controls resilience to passive cell deformation and ensures T lymphocyte survival in the blood stream. LTTN1 is, thus, a critical and versatile housekeeping regulator of T lymphocyte trafficking.

This document summarizes a study on the effects of CFTR modulators on patients with cystic fibrosis (CF) and leukocyte adhesion deficiency type IV (LAD-IV). The study found that CFTR modulators improved certain cellular functions in CF patients, suggesting that they may correct both CF and LAD-IV phenotypes. However, there were some patients who showed improvement in CF symptoms but not in LAD-IV characteristics, indicating the need for further research. The study also suggests that measuring certain cellular markers could be a useful method for monitoring patients in the long term. [Extracted from the article]

The review reports on investigations and studies that have contributed in the last 20 years (2003–2023) to the clarification of the mechanisms governing the chemical vapor generation (CVG) of hydrides and other volatile metallic species using aqueous phase derivatization with tetrahydridoborate (1-)(THB) and amine boranes, which is widely used in determination and speciation analysis of trace elements by atomic optical and mass spectrometry. The discussion begins with the early investigations leading to definition of the mechanism of hydrolysis of aqueous THB and that of reaction conditions. The new knowledge represents important achievements for the clarification of controversial aspects that plagued CVG for more than 35 years and stimulated further studies which are discussed in detail. They concern with the mechanism of hydrolysis of amine boranes, the mechanism of interferences, the role played by chemical additives and the definition of more general reaction models for CVG, which are valid for both analytical and non-analytical reaction conditions. The latest developments and the analytical applications of the new knowledge to trace element analysis are discussed. [ABSTRACT FROM AUTHOR]

This paper reports a summary of the studies on the mechanisms that govern the generation of hydrides and other volatile species through reaction with aqueous boranes (CVG). This derivatization reaction has been used since the early 1970s for elemental determination and speciation from the trace level down to the ultratrace level and below. An IUPAC project, concluded in 2011, reported on the mechanisms of hydrogen transfer from borane to the analytical substrate and served to remove erroneous concepts that had dominated CVG until the early 2000s. Following the conclusion of the IUPAC project, many studies have been published on the mechanisms of CVG under conditions approaching those of analyzes of real samples. These studies included the definition of more general reaction models, which valid under non-analytical conditions, the mechanism of action of additives and interferences in CVG of volatile hydrides. In addition to the analytical utility for CVG, the results represent a contribution to the knowledge of the chemistry of aqueous boranes. Other studies will be necessary to clarify still unknown aspects, among them the identity of volatile transition metal species formed by reaction of metal ions with aqueous boranes. [ABSTRACT FROM AUTHOR]

The negative impact of liquid phase interferences of transition metals has plagued chemical vapor generation with tetrahydridoborate since its introduction, which was more than fifty years ago. Herein, the interference from selected transition metal ions in the generation of SbH3 and BiH3 was investigated using the hydrolysis products of NaBH4-hydridoboron intermediates (BH)-as derivatization reagents instead of NaBH4. The BH intermediates were simply generated on-line in a pre-hydrolysis coil of the instrumental set-up. Compared to NaBH4, the use of BH intermediates allowed for significantly improved tolerance to the interference of Ni(II), Co(II), and Cu(II) (tolerance limit of ≥100 mg L−1) for Bi and Sb determination in the absence of any masking agents and in a wide range of acidity. Their applicability to real complex samples was successfully demonstrated by the determination of Sb and Bi in steel and copper standard reference materials. Beyond the analytical application, this work aims to play a part in the comprehension of borohydride chemical behaviour, which is still not completely understood. [ABSTRACT FROM AUTHOR]

The interaction of chemicals with DNA may lead to genotoxicity, mutation or carcinogenicity. A simple open tubular capillary electrochromatographic method is proposed to rapidly assess the interaction affinity of three environmental contaminants (1,4-phenylenediamine, pyridine and 2,4-diaminotoluene) to DNA by measuring their retention in the capillaries coated with DNA probes. DNA oligonucleotide probes were immobilized on the inner wall of a fused silica capillary that was first derivatized with 3-(aminopropyl)-triethoxysilane (APTES). The difference in retention times and factors was considered as the difference in interaction affinity of the contaminants to the DNA probes. The interaction of the contaminants with both double-stranded (dsDNA) and single-stranded DNA (ssDNA) coatings was compared. Retention factors of 1,4-phenylenediamine, pyridine and 2,4-diaminotoluene in the capillary coated with ssDNA probe were 0.29, 0.42, and 0.44, respectively. A similar trend was observed in the capillary coated with dsDNA, indicating that 2,4-diaminotoluene has the highest affinity among the three contaminants. The relative standard deviation (RSD) for the retention factors was in the range of 0.05-0.69% (n = 3). The results demonstrated that the developed technique could be applied for preliminary screening purpose to provide DNA interaction affinity information of various environmental contaminants.