The functions of metamorphic metallothioneins in zinc and copper metabolism

Recent discoveries in zinc biology provide a new platform for discussing the primary physiological functions of mammalian metallothioneins (MTs) and their exquisite zinc-dependent regulation. It is now understood that the control of cellular zinc homeostasis includes buffering of Zn2+ ions at picomolar concentrations, extensive subcellular re-distribution of Zn2+, the loading of exocytotic vesicles with zinc species, and the control of Zn2+ ion signalling. In parallel, characteristic features of human MTs became known: their graded affinities for Zn2+ and the redox activity of their thiolate coordination environments. Unlike the single species that structural models of mammalian MTs describe with a set of seven divalent or eight to twelve monovalent metal ions, MTs are metamorphic. In vivo, they exist as many species differing in redox state and load with different metal ions. The functions of mammalian MTs should no longer be considered elusive or enigmatic because it is now evident that the reactivity and coordination dynamics of MTs with Zn2+ and Cu+ match the biological requirements for controlling—binding and delivering—these cellular metal ions, thus completing a 60-year search for their functions. MT represents a unique biological principle for buffering the most competitive essential metal ions Zn2+ and Cu+. How this knowledge translates to the function of other families of MTs awaits further insights into the specifics of how their properties relate to zinc and copper metabolism in other organisms

Cukrzyca u chorego na przewlekłą białaczkę szpikową skutecznie leczonego nilotynibem

Leczenie inhibitorami kinaz tyrozynowych jest standardem postępowania w przewlekłej białaczce szpikowej. W przypadku nieskuteczności imatynibu w pierwszej linii znaczna część chorych odnosi korzyść z leczenia nilotynibem lub dasatynibem w drugiej linii, uzyskując całkowitą remisję cytogenetyczną i większą molekularną. Terapia może być jednak powikłana działaniami niepożądanymi, do których w przypadku nilotynibu należy cukrzyca. Monitorowanie wyników badań laboratoryjnych, modyfikacja stylu życia i włączenie w odpowiednim momencie leczenia przeciwcukrzycowego zapewniają możliwość dalszego skutecznego leczenia białaczki. Opisany przypadek dotyczy chorej skutecznie leczonej nitotynibem, po niepowodzeniu terapii imatynibem, u której wystąpiła cukrzyca. Zastosowanie doustnych leków przeciwcukrzycowych spowodowało poprawę i umożliwiło kontynuację leczenia nilotynibem

Remisja wolna od leczenia w praktyce klinicznej: opis grupy 6 chorych na przewlekłą białaczkę szpikową, po zaprzestaniu leczenia nilotynibem — doświadczenie jednego ośrodka

In the last 20 years major goals of therapy of chronic myelogenous leukemia (CML) have changed. This leukemia, which was previously a fatal disease, has indeed become a chronic disease thanks to the use of tyrosine kinase inhibitors (TKIs), with life expectancy close to that in the general population. Excellent treatment effectiveness with the achievement of long-term, stable, deep molecular response was the motivation for attempts to stop the therapy with the intention of maintaining remission (TFR, treatment-free remission). Based on many clinical trials with over 3,000 patients and several years of follow-up, it is known that 40–60% of patients will maintain molecular remission and remain untreated, while the rest of them will require TKI to be restarted. Information on the procedure to be followed appeared in scientific societies’ recommendations and some centers treating CML patients have made attempts to stop the therapy. This work describes a group of six patients in the TFR phase after discontinuation of nilotinib used in the first-line treatment.Cele leczenia przewlekłej białaczki szpikowej (CML) zmieniały się w ostatnich 20 latach. Białaczka ta, dzięki zastosowaniu inhibitorów kinaz tyrozynowych (TKI), z choroby śmiertelnej stała się rzeczywiście przewlekłą, z oczekiwanym czasem przeżycia bliskim średniej dla populacji. Doskonała skuteczność leczenia z uzyskaniem długotrwałej, stabilnej, głębokiej remisji molekularnej była powodem podjęcia prób zaprzestania leczenia z intencją utrzymania remisji, czyli tak zwanej remisji wolnej od leczenia (TFR). Po przeprowadzeniu wielu badań klinicznych obejmujących ponad 3000 chorych i kilkunastu latach obserwacji wiadomo, że 40–60% pacjentów utrzyma remisję molekularną i pozostanie bez leczenia, a pozostali będą wymagać ponownego włączenia TKI. Informacje dotyczące sposobu postępowania pojawiły się w rekomendacjach towarzystw naukowych i niektóre ośrodki leczące chorych na CML podjęły próby zaprzestania terapii. W niniejszej pracy opisano grupę 6 chorych w fazie TFR po odstawieniu nilotynibu stosowanego w pierwszej linii leczenia

Wykorzystanie technik data mining w analizowaniu czynników wpływających na reaktywność krów podczas doju

Motor activity of 158 Polish Holstein-Friesian cows was evaluated 5 times (before and during milking in a DeLaval 2*10 milking parlour) for both the morning and evening milking, on a 5-point scale, according to the method of Budzyńska et al. (2007). The statistical analysis used multiple logistic regression and classification trees (Enterprise Miner 7.1 software which comes in with SAS package). In the evaluation of motor activity, cows that were among the first ten to enter the milking parlour were more often given a score of 3 points before (11.5%) and during milking (23.5%) compared to the other cows. Cows’ activity tended to decrease (both before and during milking) with advancing lactation. The cows’ reduced activity was accompanied by shorter teat cup attachment times and lower milk yields. The criteria calculated for the quality of models based on classification tree technique as well as logistic regression showed that similar variables were responsible for the reactivity of cows before milking (teat cup attachment time, day of lactation, number of lactation, side of the milking parlour) and during milking (day of lactation, side of the milking parlour, morning or evening milking, milk yield, number of lactation). At the same time, the applied methods showed that the determinants of the cow reactivity trait are highly complex. This complexity may be well explained using the classification tree technique.Aktywność ruchową (przed i w czasie doju w hali udojowej DeLaval 2 * 10) 158 krów phf oceniono 5-krotnie, uwzględniając każdorazowo dój ranny i wieczorny, w skali 5 pkt., według metodyki Budzyńskiej i wsp. (2007). W opracowaniu statystycznym wykorzystano wieloraką regresję logistyczną i drzewa klasyfikacyjne (oprogramowanie Enterprise Miner 7.1 wchodzące w skład pakietu SAS). Stwierdzono, że krowy, które wchodziły do hali udojowej w pierwszej dziesiątce, w ocenie aktywności ruchowej przed i podczas doju częściej (11,5% oraz 23,5%) niż w przypadku pozostałych uzyskiwały 3 pkt. Odnotowano tendencję do zmniejszenia aktywności ruchowej krów (zarówno przed jak i w czasie doju) wraz z zaawansowaniem laktacji. Wykazano, że w wraz z mniejszą aktywnością ruchową krów skracał się czas zakładania kubków udojowych, jednocześnie też zmniejszała się wydajność mleka. Obliczone kryteria jakości modeli budowanych w oparciu o technikę drzew klasyfikacyjnych oraz regresji logistycznej wskazały podobne zmienne odpowiedzialne za reaktywność krów przed (czas zakładania kubków, kolejny dzień laktacji, kolejna laktacja i zajmowana strona hali udojowej) i w trakcie doju (kolejny dzień laktacji, zajmowana strona hali udojowej, dój ranny lub wieczorny, wydajność mleka oraz kolejna laktacja). Jednocześnie zastosowane metody wskazały znaczną złożoność uwarunkowania cechy, jak jest reaktywność krów. Złożoność ta może być dobrze wyjaśniona za pomocą techniki drzew klasyfikacyjnych

Interactions of Zn(II) Ions with Three His-Containing Peptide Models of Histone H2A

The interactions of Zn(ll) ions with the blocked hexapeptide models -TESHHK-, -TASHHK- and -TEAHHK- of the -ESHH- motif of the C-terminal of historic H2A were studied by using potentiometric and IH-NMR techniques. The first step of these studies was to compare the pKa values of the two His residues inside each hexapeptide calculated by potentiometric or H-NMR titrations. Hereafter, the potentiometric titrations in the pH range 5 11 suggest the formation of several monomeric Zn(ll) complexes. It was found that all hexapeptides bind to Zn(ll) ions initially through both imidazole nitrogens in weakly acidic and neutral solutions forming slightly distorted octahedral complexes. At higher pH values, the combination of potentiometric titrations and one and two dimensional NMR suggested no amide coordination in the coordination sphere of Zn(II) ions. Obviously, these studies support that the -ESHH- sequence of histone H2A is a potential binding site for Zn(II) ions similarly with the Cu(II) and Ni(ll) ions, presented in previous papers

Interdependence of the Rad50 hook and globular domain functions

Rad50 contains a conserved Zn2+ coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here we focused on rad50 mutations flanking the Zn2+-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end-joining, and DNA double strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled coil and globular ATPase domain, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions

An Extremely Stable Interprotein Tetrahedral Hg(Cys) ₄ Core Forms in the Zinc Hook Domain of Rad50 Protein at Physiological pH

In nature, thiolate-based systems are the primary targets of divalent mercury (HgII ) toxicity. The formation of Hg(Cys)x cores in catalytic and structural protein centers mediates mercury's toxic effects and ultimately leads to cellular damage. Multiple studies have revealed distinct HgII -thiolate coordination preferences, among which linear HgII complexes are the most commonly observed in solution at physiological pH. Trigonal or tetrahedral geometries are formed at basic pH or in tight intraprotein Cys-rich metal sites. So far, no interprotein tetrahedral HgII complex formed at neutral pH has been reported. Rad50 protein is a part of the multiprotein MRN complex, a major player in DNA damage-repair processes. Its central region consists of a conserved CXXC motif that enables dimerization of two Rad50 molecules by coordinating ZnII . Dimerized motifs form a unique interprotein zinc hook domain (Hk) that is critical for the biological activity of the MRN. Using a series of length-differentiated peptide models of the Pyrococcus furiosus zinc hook domain, we investigated its interaction with HgII . Using UV-Vis, CD, PAC, and 199 Hg NMR spectroscopies as well as anisotropy decay, we discovered that all Rad50 fragments preferentially form homodimeric Hg(Hk)2 species with a distorted tetrahedral HgS4 coordination environment at physiological pH; this is the first example of an interprotein mercury site displaying tetrahedral geometry in solution. At higher HgII content, monomeric HgHk complexes with linear geometry are formed. The Hg(Cys)4 core of Rad50 is extremely stable and does not compete with cyanides, NAC, or DTT. Applying ITC, we found that the stability constant of the Rad50 Hg(Hk)2 complex is approximately three orders of magnitude higher than those of the strongest HgII complexes known to date

Deep molecular response on imatinib treatment — results from a real-life retrospective study

Introduction: Tyrosine kinase inhibitors (TKIs) have dramatically changed the outcome of chronic myeloid leukemia (CML) patients. Recent research focused on TKI discontinuation after achieving a deep molecular response (DMR) has revealed that about half of the patients maintain the response. DMR is a key criterion for TKI discontinuation. Our retrospective, ‘real-life’ study was aimed at to estimating the proportion of patients treated with first-line imatinib (IM) who achieved DMR and thus may be candidates for discontinuation of TKI treatment in a real life setting. Material and methods: Two hundred and twenty-three patients were enrolled. All patients started IM at 400 mg daily. The median age at the time of diagnosis was 57 years (range: 17–92). Results: Eighty-five patients (43%) in the whole group achieved DMR. Early molecular response (EMR) was achieved by 136 (69%) patients and correlated with the DMR rate (53% with EMR vs 14% without, p < 0.001). Major molecular response (MMR) after a year of treatment was confirmed in 108 (55%) patients, and was predictive for achieving DMR at any time (69% with MMR vs. 24% without, p < 0.001). Conclusion: DMR can be achieved in a significant proportion of patients in a real-life setting. We observed that both the achievement of an EMR at three months and MMR at 12 months were associated with a significant advantage in terms of DMR

Triggering redox activity in a thiophene compound: radical stabilization and coordination chemistry

The synthesis, metalation, and redox properties of an acyclic bis(iminothienyl)methene L− are presented. This π-conjugated anion displays pronounced redox activity, undergoing facile one-electron oxidation to the acyclic, metal-free, neutral radical L* on reaction with FeBr2. In contrast, reaction of L− with CuI forms the unique, neutral Cu2I2(L*) complex of a ligand-centered radical, whereas reaction with the stronger oxidant AgBF4 forms the metal-free radical dication L*2+