Biomedical subjects

Mladen Birus

Publications and source records attributed to Mladen Birus.

4 recordsLinked to original sources

PubMed2006

Cyclic trihydroxamic acid derivatives.

In the crystal structures of two cyclic trihydroxamic acid derivatives containing the same substructure unit, viz. 1,3,5-trihydroxy-1,3,5-triazinane-2,4,6-trione dihydrate, C3H3N3O6.2H2O, (I), and 1,3,5-benzyloxy-1,3,5-triazinane-2,4,6-trione, C24H21N3O6, (II), there is no significant difference in the geometric parameters. In (I), there are 11 hydrogen bonds of the O-H...O type interconnecting the molecules in a three-dimensional network, while in (II) there are only two weak C-H...O hydrogen bonds. The results of IR spectroscopic analysis are in good agreement with the crystallographic study.

Acids↗

PubMed2006

Oxidation of hydroxyurea with oxovanadium(V) ions in acidic aqueous solution.

Hydroxyurea (HU) effectively reduces vanadium(V) into vanadium(IV) species (hereafter V(V) and V(IV) species, respectively) in acidic aqueous solution via the formation of a transient complex followed by an electron transfer process that includes the formation and subsequent fading out of a free radical, U* (U* identical with H(2)N-C(=O)N(H)O*). The electron paramagnetic resonance (EPR) spectra of U* in H(2)O/D(2)O solutions suggest that the unpaired electron is located predominantly on the hydroxamate hydroxyl-oxygen atom. Visible and V(IV)-EPR spectroscopic data reveal HU as a two-electron donor, whereas formation of U*, which reduces a second V(V), indicates that electron transfer occurs in two successive one-electron steps. At the molarity ratio [V(V)]/[HU]=2, the studied reaction can be formulated as: 2 V(V)+HU-->2 V(IV)+0.98 CO(2)+0.44 N(2)O+1.1 NH(3)+0.1 NH(2)OH. Lack of evidence for the formation of NO is suggested to be a consequence of the slow oxidation of HNO due to the too low reduction potential of the V(V)/V(IV) couple under the experimental conditions used. The nuclear magnetic resonance ((51)V-NMR) spectral data indicate protonation of (H(2)O)(4)V(V)O(2)(+), and the protonation equilibrium constant was determined to be K=0.7 M(-1). Spectrophotometric titration data for the V(V)-HU system reveal formation of (H(2)O)(2)V(V)O(OH)U(+) and (H(2)O)(3)V(V)OU(2+). Their stability constants were calculated as K(110)=5 M(-1) and K(111)=22 M(-2), where the subscript digits refer to (H(2)O)(4)V(V)O(2)(+), HU and H(+), respectively.

Electron Spin Resonance Spectroscopy↗

PubMed2005

Prescribing medication errors in hospitalised patients: a prospective study.

The aims of this prospective study were to determine the incidence and types of prescribing medication errors and ways to prevent them from reaching patients. Data were collected from 4951 prescriptions over a 25 week period in 2002. Medication errors were classified as: incorrect dose, incorrect dose interval, duplication of therapy and drug interactions. The medical record analysis was used to compare prescribing with Croatian literature drug data and AHFS first Web version 2 (American Society of Health System Pharmacists). The incidence of medication errors in the entire sample, including all potential drug interactions, was 14.7%. However, as only 8 interactions (out of 356 potentially possible interactions) were assessed as clinically significant, then the total number of all types of medication errors was 379. This resulted in an incidence of 7.7%. Dosage errors were the most frequent errors, followed by incorrect interval, drug duplication and drug interaction. The difference between the incidence of potentially possible and clinically significant drug interactions was quite large (7.2 vs. 0.2%). Thus, a critical attitude is necessary when evaluating available data on drug interactions. Our findings point to the need of systematic control of prescribed therapies, which could be ensured by the application of the Unit Dose Drug Distribution System. A medication errors reporting program should be established both at the hospital and at national levels in Croatia.

Adult↗

PubMed2003

Betainohydroxamic acid chloride.

The title compound, N-hydroxy-2-(trimethylammonio)acetamide chloride, C(5)H(13)N(2)O(2)(+).Cl(-), has been synthesized and structurally characterized. The structure consists of betainohydroxamic acid cations and Cl(-) anions linked by N-H.Cl and O-H.Cl hydrogen bonds into chains along [001]. It was found that the positive inductive effect of the charged N atom in close proximity to the hydroxamate carbonyl O atom has a negligible effect on the hydroxamic C-N bond length.

Journal Article↗