Search

Background: Growth hormone (GH) has been used to treat children with GH deficiency (GHD) since 1966., Aims: Using a combined retrospective and cross-sectional approach, we explored the long-term outcomes of patients with GHD, analysed factors influencing therapeutic response, determined persistence into adulthood, investigated pituitary morphology, and screened for mutations in causative genes., Methods: The files of 96 GH-deficient children were reviewed. In a subset of 50 patients, re-assessment in adulthood was performed, including GHRH-arginine testing, pituitary magnetic resonance imaging (MRI), and mutational screening for the growth hormone-1 gene (GH1) and the GHRH receptor gene (GHRHR) in isolated GHD (IGHD), and HESX1, PROP1, POU1F1, LHX3, LHX4, and GLI2 in multiple pituitary hormone deficiency (MPHD) patients., Results: GH was started at a height SDS of -3.2 ± 1.4 in IGHD patients and of -4.1 ± 2.1 in MPHD patients. Relative height gain was 0.3 SDS/year, absolute gain 1.6 SDS, and 1.2/2.6 SDS in IGHD/MPHD, respectively. Mid-parental target height was reached in 77%. Initial height SDS, bone age retardation and duration of GH replacement were correlated with height SDS gain. GHD persisted into adulthood in 19 and 89% of subjects with IGHD and MPHD, respectively. In 1/42 IGHD patients a GH1 mutation was detected; PROP1 mutations were found in 3/7 MPHD subjects. Anterior pituitary hypoplasia, combined with posterior pituitary ectopy and pituitary stalk invisibility on MRI, was an exclusive finding in MPHD patients., Conclusions: GH replacement successfully corrects the growth deficit in children with GHD. While the genetic aetiology remains undefined in most cases of IGHD, PROP1 mutations constitute a major cause for MPHD. Persistence of GHD into adulthood is related to abnormal pituitary morphology., (© 2016 S. Karger AG, Basel.)

The objective of this study was to establish a new test system for the monitoring of platelet aggregation during extracorporeal circulation (ECC) procedures. Even though extensive progress has been made in improving the haemocompatibility of extracorporeal circulation devices, activation of blood coagulation, blood platelets and inflammatory responses are still undesired outcomes of cardiopulmonary bypass. This study deals with an approach towards a platelet aggregation measuring system using a newly developed quartz crystal microbalance (QCM) system. Since QCM is a rarely used technique in the field of blood analytics, the challenge was to transfer the well established methods of aggregometry to the new test system. In a QCM system, either bare gold or fibrinogen-coated sensors were incubated with ADP or arachidonic acid (AA) stimulated platelet rich plasma. For negative controls the GPIIb/IIIa inhibitory antibody abciximab (Reopro®) was used as an inhibitor of platelet aggregation. During incubation, the frequency shifts of the sensors were recorded. The results gained from the QCM system were compared to results gained by optical platelet aggregometry (born aggregometry). For additional visualization of platelet adhesion to the sensor surfaces, fluorescent microscopy and scanning electron microscopy were used. The QCM sensor was able to detect platelet aggregation in both uncoated and fibrinogen coated sensors. The measuring curves of aggregation measurements and controls were clearly distinguishable from each other in terms of frequency shifts and kinetics. For aggregation measurements and inhibited controls the therapeutic diagnosis of platelet function is identical between aggregometer and QCM data. In future, QCM based measuring devices may become an alternative to established point of care methods for rapid bedside testing of platelet aggregation.

Monitoring of blood coagulation and fibrinolysis is an important issue in treatment of patients with cardiovascular problems and in surgery when blood gets into contact with artificial surfaces. In this work a new method for measuring the coagulation time (prothrombin time, PT) of human whole-blood samples based on a quartz crystal microbalance (QCM) biosensor is presented. The 10 MHz sensors used in this work respond with a frequency shift to changes in viscosity during blood clot formation. For driving and for readout of the quartz, both a network analyzer and an oscillator circuit were utilized. The sensor surfaces were specifically coated with a thin polyethylene layer. We found that both frequency analysis methods are suitable to measure exact prothrombin times in a very good conformity with a mechanical coagulometer as a reference. The anticoagulant effect of heparin on the prothrombin time was exemplarily shown as well as the reverse effect of the heparin antagonist polybrene. The change of the viscoelastic properties during blood coagulation, reflected by the ratio of frequency and dissipation shifts, is discussed for different dilutions of the whole-blood samples. In conclusion, QCM is a distinguished biosensor technique to determine prothrombin time and to monitor heparin therapy in whole-blood samples. Due to the excellent potential of miniaturization and the availability of direct digital signals, the method is predestinated for incorporation and integration into other devices and is thus opening the field of application for inline coagulation diagnostic in extracorporeal blood circuits.

Staphyloferrin A, the iron-transporting siderophore of Staphylococci, contains two citric acid residues linked to a D-ornithine backbone, having thus three chiral centers. While the chirality of the backbone can be determined after hydrolysis, the chirality of the two citryl residues can only be determined from the intact staphyloferrin A molecule by circular dichroism spectra. The chirality of the quarternary carbon atoms of citryl residues in fungal rhizoferrin and bacterial enantio-rhizoferrin have been determined previously to be R,R and S,S respectively. The present investigation shows that of the three chiral centers in staphyloferrin A, the citryl residues can be assigned an S,S-configuration by comparison with synthetic analogs, confirming a common chirality among the bacterial enantio-rhizoferrin and staphyloferrin A. This suggests that the bacterial carboxylates originate from a common biosynthetic pathway leading to an S,S-configuration, while the fungal rhizoferrin possessing an R,R-configuration must have a different biosynthetic origin. Growth promotion tests with staphylococci revealed that the S,S-configuration of staphyloferrin A and enantio-rhizoferrin enabled iron uptake, while the fungal rhizoferrin with R,R-configuration was not utilized.

Iron complexes of daunorubicin, idarubicin, pirarubicin, and doxorubicin in anhydrous DMF were studied by UV/vis, CD, fluorescence, Mössbauer, and EPR spectroscopy. Titration studies of the metal-free anthracyclines showed one (UV-detectable) deprotonation step requiring 2 equiv of base, compared to 1 equiv for quinizarine. Metal complexation was studied at three different metal/ligand ratios, and with increasing amounts of base. The results obtained from optical spectroscopy show the existence of two different complex species and give clear indications for the requirements of metal complexation. Complex species I, formed at a low iron-to-ligand ratio, is less dependent on base addition than complex species II formed with equimolar ferric ion. EPR and Mössbauer experiments provide further insight into the structures of both complex species. Lack of spin density of the Mössbauer samples in EPR indicates spin coupling between the metal centers. Mössbauer spectra consist of single quadrupole doublets with values typical for high-spin ferric ion in an octahedral arrangement. The Mössbauer spectroscopic features at 7 T exclude the presence of S = 0 dimers. Complex I represents a monomeric ferric iron complex whereas complex II is consistent with a more or less aggregrated oligomeric Fe-anthracycline system.

We report here on a new class of siderophores isolated from Rhodococcus erythropolis IGTS8, the first structurally characterized from any species of Rhodococcus and for which we suggest the name heterobactins. These siderophores consist of a tripeptide of sequence (N-OH)-L-Orn-Gly-D-Orn-(delta-N-dihydroyxbenzoate). The alpha amino group of the D-Orn is derivatized either as a 2-hydroxybenzoxazolate in heterobactin A or remains free in heterobactin B. The structures were determined by a combination of amino acid analysis, mass spectrometry and NMR methods. The two new compounds are true siderophores in that they relieve iron limited growth in the producing strain. The heterobactins are also transported by other non-producing bacteria. Growth promotion tests using various transport mutants revealed that in E. coli heterobactin A is only recognized by the catecholate receptor Cir while heterobactin B is taken up in both E.coli and A. flavescens JG9 via a hydroxamate transport system.

The interaction of Fe(3+) with the anthracycline anticancer drug idarubicin (Ida) was studied by absorption, CD, Mössbauer, and EPR spectroscopy. The formation of two major Fe(3+)-Ida complexes, labeled I and II, was observed. In complex I, Fe(3+) ion was bound to anthracycline at the {C(12)=O; C(11)-O(-)} coordination site. In complex II, two Fe(3+) ions were bound at sites {C(5)=O; C(6)-O(-)} and {C(12)=O; C(11)-O(-)}, respectively. Complex I was an equimolar monomeric species with a 1:1 Fe(3+):Ida stoichiometry (beta(1) = 4.8 x 10(11) M(-1)), whereas in complex II the anthracycline ligand was bridging two metal ions, alternatively bound to both anthracycline ring chelating sites with the assumption that the ratio of Fe(3+):Ida in complex II was 2:1 (beta(2) = 5.3 x 10(24) M(-2)). Alternatively, complex II may be oligomeric with Fe(3+):Ida = 1:1 and with each Fe(3+) bridging two Ida molecules. Our findings could be important in understanding the biological effects of the anthracycline-ferric complexes. Thus, providing information about the nature of the Fe(3+)-Ida system, we suggest that the formal 1:3 Fe(3+):anthracycline complexes, reported in the previous literature, could be a mixture of species I, II, and free ligand.

Rhizoferrin is a member of a new class of siderophores (microbial iron transport compounds) based on carboxylate and hydroxy donor groups rather than the commonly encountered hydroxamates and catecholates. We have studied the coordination chemistry of rhizoferrin (Rf), as a representative of this group, with Fe(3+), Rh(3+), Cr(3+), Al(3+), Ga(3+), VO(2+), and Cu(2+). The metal complexes have been studied by UV-vis, CD, NMR, and EPR spectroscopies and mass spectrometry. The formation constants for the iron complex have also been measured and yield a log K(LFe) of 25.3. The Rh and Cr rhizoferrin complexes are unusual in that they appear to adopt a chirality about the metal center that is the opposite of the native iron analog. Several of the alternative metal ion complexes are found to have biological activity toward Morganella morganii in a plate type assay.

This paper describes the chemical characterization of staphyloferrin B, a new complexone type siderophore isolated from low iron cultures of Staphylococcus hyicus DSM 20459. Purification of the very hydrophilic metabolite was achieved by anion exchange high performance liquid chromatography HPLC. Mass spectrometry showed a molecular mass of 448 amu. Hydrolysis with 8 M HCl revealed the presence of L-2,3-diaminopropionic acid, citrate, ethylenediamine and succinic semialdehyde. The connections between the four building blocks were determined by two-dimensional nuclear magnetic resonance measurements. UV/Vis and circular dichroism spectra are consistent with the proposed structure, which could also be confirmed by precursor feeding. The siderophore activity of staphyloferrin B was demonstrated by iron transport measurements.