The Non-Ancillary Nature of Trimethylsilylamide Substituents in Boranes and Borinium Cations.

The known boranes (R(Me3 Si)N)2 BF (R=Me3 Si 1, tBu 2, C6 F5 3, o-tol 4, Mes 5, Dipp 6) and borinium salts (R(Me3 Si)N)2 B][B(C6 F5 )4 ] (R=Me3 Si 7, tBu 8) are prepared and fully characterized. Compound 7 is shown to react with phosphines to generate [R3 PSiMe3 ]+ and [R3 PH]+ (R=Me, tBu). Efforts to generate related borinium cations via fluoride abstraction from (R(Me3 Si)N)2 BF (R=C6 F5 3, o-tol 4, Mes 5) gave complex mixtures suggesting multiple reaction pathways. However for R=Dipp 6, the species [(µ-F)(SiMe2 N(Dipp))2 BMe][B(C6 F5 )4 ] was isolated as the major product, indicating methyl abstraction from silicon and F/Me exchange on boron. These observations together with state-of-the-art DFT mechanistic studies reveal that the trimethylsilyl-substituents do not behave as ancillary subsitutents but rather act as sources of proton, SiMe3 and methyl groups.

Comparison of immunohistochemistry and gene expression profiling subtyping for diffuse large B-cell lymphoma in the phase III clinical trial of R-CHOP ± ibrutinib.

We assessed the concordance between immunohistochemistry (IHC) and gene expression profiling (GEP) for determining diffuse large B-cell lymphoma (DLBCL) cell of origin (COO) in the phase III PHOENIX trial of rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) with or without ibrutinib. Among 910 of 1114 screened patients with non-germinal centre B cell-like (non-GCB) DLBCL by IHC, the concordance with GEP for non-GCB calls was 82·7%, with 691 (75·9%) identified as activated B cell-like (ABC), and 62 (6·8%) as unclassified. Among 746 of 837 enrolled patients with verified non-GCB DLBCL by IHC, the concordance with GEP was 82·8%, with 567 (76·0%) identified as ABC and 51 (6·8%) unclassified; survival outcomes were similar regardless of COO or treatment, whereas among patients with ABC DLBCL aged <60 years, the overall and event-free survival were substantially better with ibrutinib versus placebo plus R-CHOP [hazard ratio (HR) 0·365, 95% confidence interval (CI) 0·147-0·909, P = 0·0305; HR 0·561, 95% CI 0·326-0·967, P = 0·0348, respectively]. IHC and GEP showed high concordance and consistent survival outcomes among tested patients, indicating centralised IHC may be used to enrich populations for response to ibrutinib plus R-CHOP.

A chelated borinium cation.

Two coordinate boron cations are rare. Herein we report the synthesis of [RNSiMe2CH2]2BF (R = Dipp 3, 1-Ad 5) (Dipp = C6H3(iPr)2, Ad = C10H15) via the reaction of BF3 with the corresponding dilithiated diamides. Subsequent abstraction of fluoride provided the corresponding borinium salts, [(RNSiMe2CH2)2B][B(C6F5)4] (R = Dipp 6, 1-Ad 8). While the former was generated, the latter proved isolable and was crystallographically characterized.

Correction: A chelated borinium cation.

Correction for 'A chelated borinium cation' by Christopher Major et al., Dalton Trans., 2024, 53, 10075-10078, https://doi.org/10.1039/D4DT01242A.

Boron diamide derivatives containing N-N and N-P molecular fragments.

The cationic and neutral boron-diamide precursors are employed to target the inclusion of N2 and N-P molecular fragments. The species (HCN(Dipp))2BNH25, and (H2CN(Dipp))2BNH26 were prepared. While efforts to oxidize with [NO]+ gave mixtures of products, reactions with N2H4 gave the salts [(HCN(Dipp))2B(NHNH3)][O3SCF3] 7 [(H2CN(Dipp))2B(NHNH3)][O3SCF3] 8. Excess N2H4 gave the neutral species (HCN(Dipp))2B(NHNH2) 9 and (H2CN(Dipp))2B(NHNH2) 10, respectively. The species (H2CN(Dipp))2B(N3) 11 was prepared for comparative purposes. Turning to related NP species, compound 6 was converted to (HCN(Dipp))2B(NHPCl2) 12, while (HCN(Dipp))2BNK(SiMe3) 14 was used to give (HCN(Dipp))2BN(SiMe3)PCl215. Replacement of one of the chlorides gave (HCN(Dipp))2BN(SiMe3)PCl(OSO2CF3) 16 which converts to [(HCN(Dipp))2BNPCl]217. Similarly heating 15 afforded 17. The insights for the synthesis of further boron-N2 and boron-NP derivatives are discussed.

Identifying fibroblast growth factor receptor genetic alterations using RNA-based assays in patients with metastatic or locally advanced, surgically unresectable, urothelial carcinoma who may benefit from erdafitinib treatment.

Erdafitinib, a pan-fibroblast growth factor receptor (FGFR) inhibitor received accelerated approval from the US Food and Drug Administration (FDA) for locally advanced or metastatic urothelial carcinoma (mUC) in adult patients with specific FGFR3/2 genetic alterations who progressed during or after ≥1 line of prior platinum-containing chemotherapy (PCC), including within 12 months of neoadjuvant or adjuvant PCC. Concordance between the clinical trial assay (CTA) used in a phase 2 study and QIAGEN's therascreen® FGFR kit (a two-step, multiplex, real-time, RT-PCR assay), the FDA-approved companion diagnostic (CDx) with erdafitinib, was evaluated in this bridging study. Study samples included 100 CTA-confirmed FGFR-positive samples from 100 erdafitinib-treated mUC patients, plus 200 CTA-confirmed FGFR-negative samples from the phase 2 study. The primary objective was met if the lower bound of 95% CI of objective response rate (ORR) in CDx-confirmed patients with FGFR alterations was >25%. Demographics were similar between the bridging study and CTA-screened patients. In total, 292 of 300 samples (97.3%) with valid CDx results showed high analytical concordance versus CTA (percent agreement [95% CI]: positive percent agreement, 87.2 [79.0; 92.5]; negative percent agreement, 97.0 [93.5; 98.6]; overall percent agreement, 93.8 [90.5; 96.1]). Investigator-assessed ORR in the 81 CDx-identified, erdafitinib-treated patients who tested positive for both assays was 45.7% (95% CI: 35.3%; 56.5%) versus 40.4% (95% CI: 30.7%; 50.1%) for CTA and met the criteria for primary objective. High ORR and clinical concordance to CTA suggest that QIAGEN's CDx can reliably select mUC patients who would potentially benefit from erdafitinib treatment.

Hydroboration without a B-H bond: reactions of the borinium cation [(iPr2N)2B]+ with alkyne, nitrile, ketone and diazomethane.

The borinium cation [(iPr2N)2B]+ (1+) is shown to react with PhCCH, PhCN, Ph2CO, and Ph2CN2 to effect a net hydroboration, affording borenium complexes of the form [(iPr2N)B(iPrN[double bond, length as m-dash]CMe2)(L)][B(C6F5)4] (L = CH[double bond, length as m-dash]CHPh 2, N[double bond, length as m-dash]CHPh 3, OCHPh24, NHNCPh25). The nature and reaction of 1+ with PhCCH was probed computationally and the reduction of these unsaturates is shown to occur via hydride transfer from an isopropyl group to the alkyne, thus effecting hydroboration without a B-H bond.

Extracellular mediators in atherosclerosis and thrombosis: lessons from thrombin receptor knockout mice.

It is well appreciated that thrombin as well as other proteases can act as signaling molecules that specifically regulate cells by cleaving and activating members of a novel class of protease-activated receptors (PARs). The utility of gene knockout strategies to define and better comprehend the physiological role of specific proteins is perhaps best exemplified in the field of thrombin receptors. The development of PAR knockout mice has provided the unique opportunity to identify and characterize new members of this novel family of GPCRs, evaluate the interaction of PARs jointly expressed in common cells and tissues, and better understand the role of PARs in thrombosis, restenosis, vascular remodeling, angiogenesis, and inflammation. Presently, 4 members of the PAR family have been cloned and identified. In this review, we examine experimental evidence gleaned from PAR-/- mouse models as well as how the use of PAR-/- mice has provided insights toward understanding the physiological role of thrombin in cells of the vascular system and vascular pathology.

Traumatic hand fracture in a patient with osteogenesis imperfecta.

OBJECTIVE: This article presents a case of osteogenesis imperfecta and reviews the clinical and radiographic features of this condition. CLINICAL FEATURES: A 27-year-old woman presented with pain in her left hand after a fall while dancing. Plain films revealed multiple fractures in the digits of her left hand. INTERVENTION AND OUTCOME: The patient was referred to an orthopedic specialist for treatment. CONCLUSION: Osteogenesis imperfecta is a heritable disorder of bone, which predisposes patients to fractures after trivial trauma, as was demonstrated in this case.

SB-505124 is a selective inhibitor of transforming growth factor-beta type I receptors ALK4, ALK5, and ALK7.

Clinically, there is a great need for small molecule inhibitors that could control pathogenic effects of transforming growth factor (TGF-beta) and/or modulate effects of TGF-beta in normal responses. Inhibition of TGF-beta signaling would be predicted to enhance re-epithelialization of cutaneous wounds and reduce scarring fibrosis. Selective small molecule inhibitors of the TGF-beta signaling pathway developed for therapeutics will also be powerful tools in experimentally dissecting this complex pathway, especially its cross-talk with other signaling pathways. In this study, we characterized 2-(5-benzo[1,3]dioxol-5-yl-2-tert-butyl-3H-imidazol-4-yl)-6-methylpyridine hydrochloride (SB-505124), a member of a new class of small molecule inhibitors related to imidazole inhibitors of p38, which inhibit the TGF-beta type I receptor serine/threonine kinase known as activin receptor-like kinase (ALK) 5. We demonstrate that this compound selectively and concentration-dependently inhibits ALK4-, ALK5-, and ALK 7-dependent activation of downstream cytoplasmic signal transducers, Smad2 and Smad3, and of TGF-beta-induced mitogen-activated protein kinase pathway components but does not alter ALK1, ALK2, ALK3 or ALK6-induced Smad signaling. SB-505124 also blocks more complex endpoints of TGF-beta action, as evidenced by its ability to abrogate cell death caused by TGF-beta1 treatment. SB-505124 is three to five times more potent than a related ALK5 inhibitor described previously, SB-431542.

Interference with transforming growth factor-beta/ Smad3 signaling results in accelerated healing of wounds in previously irradiated skin.

Transforming growth factor (TGF)-beta regulates many aspects of wound repair including inflammation, chemotaxis, and deposition of extracellular matrix. We previously showed that epithelialization of incisional wounds is accelerated in mice null for Smad3, a key cytoplasmic mediator of TGF-beta signaling. Here, we investigated the effects of loss of Smad3 on healing of wounds in skin previously exposed to ionizing radiation, in which scarring fibrosis complicates healing. Cutaneous wounds made in Smad3-null mice 6 weeks after irradiation showed decreased wound widths, enhanced epithelialization, and reduced numbers of neutrophils and myofibroblasts compared to wounds in irradiated wild-type littermates. Differences in breaking strength of wild-type and Smad3-null wounds were not significant. As shown previously for neutrophils, chemotaxis of primary dermal fibroblasts to TGF-beta required Smad3, but differentiation of fibroblasts to myofibroblasts by TGF-beta was independent of Smad3. Previous irradiation-enhanced induction of connective tissue growth factor mRNA in wild-type, but not Smad3-null fibroblasts, suggested that this may contribute to the heightened scarring in irradiated wild-type skin as demonstrated by Picrosirius red staining. Overall, the data suggest that attenuation of Smad3 signaling might improve the healing of wounds in previously irradiated skin commensurate with an inhibition of fibrosis.

Mice lacking Smad3 are protected against cutaneous injury induced by ionizing radiation.

Transforming growth factor-beta (TGF-beta) plays a central role in the pathogenesis of inflammatory and fibrotic diseases, including radiation-induced fibrosis. We previously reported that mice null for Smad3, a key downstream mediator of TGF-beta, show accelerated healing of cutaneous incisional wounds with reduced inflammation and accumulation of matrix. To determine if loss of Smad3 decreases radiation-induced injury, skin of Smad3+/+ [wild-type (WT)] and -/- [knockout (KO)] mice was exposed to a single dose of 30 to 50 Gy of gamma-irradiation. Six weeks later, skin from KO mice showed significantly less epidermal acanthosis and dermal influx of mast cells, macrophages, and neutrophils than skin from WT littermates. Skin from irradiated KO mice exhibited less immunoreactive TGF-beta and fewer myofibroblasts, suggesting that these mice will have a significantly reduced fibrotic response. Although irradiation induced no change in the immunohistochemical expression of the TGF-beta type I receptor, the epidermal expression of the type II receptor was lost after irradiation whereas its dermal expression remained high. Primary keratinocytes and dermal fibroblasts prepared from WT and KO mice showed similar survival when irradiated, as did mice exposed to whole-body irradiation. These results suggest that inhibition of Smad3 might decrease tissue damage and reduce fibrosis after exposure to ionizing irradiation.