6 research outputs found
Cranial MRI in Childhood Acute Leukemia during Treatment and Follow-Up Including the Impact of Intrathecal MTX : A Single-Center Study and Review of the Literature
Due to high survival rates, long-term sequelae, especially neurotoxicity, need to be considered in childhood acute leukemias. In this retrospective analysis of morphologic changes of the
brain in children treated for acute leukemias, we included 94 patients (77 ALL, 17 AML; 51 male,
43 female; median age: 5 years) from a single center. We analyzed 170 cranial MRI scans (T2, FLAIR
axial) for morphologic alterations of the brain and variations of the ventricular width (GDAH). In
addition, the corresponding literature was reviewed. More than 50% of all patients showed cerebral
pathomorphologies (CP). They were seen more often in children with ALL (55.8%), †6 years of age
(60.8%), in relapse (58.8%) or after CNS irradiation (75.0%) and included white matter changes, brain
atrophy, sinus vein thrombosis and ischemic events. GDAH significantly enlarged mainly in children
up to 6 years, with relapse, high-risk leukemias or ALL patients. However, GDAH can normalize
again. The number of intrathecal Methotrexate applications (â€12 vs. >12) showed no correlation to
morphologic alterations besides a significant increase in GDAH (â0.3 vs. 0.9 mm) between the first
and last follow-up MRI in ALL patients receiving >12 ith. MTX applications. The role of ith. MTX on
CP needs to be further investigated and correlated to the neurocognitive outcome of children with
acute leukemias
Between imide, imidyl and nitrene â an imido iron complex in two oxidation states
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive CâH bonds
as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes
[Fe(NMes)L2]0,- (L ÂŒ âN{Dipp}SiMe3); Dipp ÂŒ 2,6-diisopropyl-phenyl; Mes ÂŒ (2,4,6-trimethylphenyl) via
reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,-. UV-vis-, EPR-, 57Fe Mšossbauer
spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic
structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III)
imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are
capable of H atom abstraction from CâH bonds. Further, the reduced form [Fe(NMes)L2]- reacts
nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under
nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced
by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity
Between imide, imidyl and nitrene â an imido iron complex in two oxidation states
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive CâH bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,â (L = âN{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,â. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III) imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from CâH bonds. Further, the reduced form [Fe(NMes)L2]â reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity