PubMed Health⌕ Search

Biomedical subjects

U Krajewska

Publications and source records attributed to U Krajewska.

7 recordsLinked to original sources
PubMed2001

Partition coefficients of alkyl aromatic hydrocarbons and esters in a hexane-acetonitrile system.

Partition coefficients (Kp) in a heterogeneous system consisting of two immiscible organic solvents can be successfully used for a supplementary identification parameter in qualitative GC and GC-MS analysis of organic compounds. For rapid addition to database of Kp values, calculation methods based on the well-known 'retention-structure relationships' approach can be used. This paper reports the experimentally determined and calculated Kp values for 252 compounds including alkyl aromatic hydrocarbons and esters. It is shown that for group identification of components it is desirable to use not the Kp values themselves but the parameter j which is a combination of K, and gas chromatographic retention indices: j = kI - log Kp.

Acetonitriles↗
PubMed1997

Platelet activation by mercuric compounds.

We previously showed that at low concentrations (0.01-10 micromol/l) mercury (Hg) compounds (especially methylmercuric chloride) may act synergistically with physiological agonists to activate platelets and may also cause changes in blood coagulation in experimental animals. Result obtained in this study indicate that the activation of pig blood platelets by methylmercuric chloride (MMC) is not dependent on membrane receptors for fibrinogen and ADP. Furthermore, we have calculated that pig platelets take up approximately 13-fold more Hg than plasma proteins during incubation of platelet-rich plasma with MMC. These findings may explain the recently reported link between vascular events and Hg poisoning.

Journal Article↗
PubMed1997

Expression of 65-kDa oncofetal protein in experimental hepatoma after anticancer therapy.

We have tested the expression of a 65-kDa oncofetal protein (p65) after combined treatment with menadione and methotrexate in hamsters transplanted with Kirkman-Robins hepatoma. The treatment of tumor-bearing animals with these compounds significantly inhibited both the tumor development and the expression of p65. This inhibition in tumor tissue was calculated from densitograms of Western blots. The inhibition of p65 expression was also confirmed in the serum of hepatoma bearing animals by using solid-phase radioimmunoassay (RIA) to quantify the specificity of polyclonal antibodies to fetal p65 molecules. Additionally, p65 was shown to localize both in cytoplasm and in the nuclear extracts prepared from hepatoma tissue.

Animals↗
PubMedDate not supplied

Gas chromatographic analysis of essential oils with preliminary partition of components.

The efficiency of using combinations of retention indices and partition coefficients (Kp) with a hexane: acetonitrile system has been demonstrated by taking as an example the essential oil from Artemisia pallens Wall. Preliminary partition of the components between the two partly mixing liquids provides information by which components can be attributed to the appropriate homologous series. The use of group constants (j), which are functions of both partition coefficients and GC retention indices, in the practice of identifying the components of essential oils is reported for the first time.

Chromatography, Gas↗
PubMedDate not supplied

Blood coagulation changes in rats poisoned with methylmercuric chloride (MeHg).

The effects of methylmercuric chloride on the coagulability of blood were studied in rats. The administration of a single dose (17.9 mg Hg/kg) and a repeated dose (5 X 8 mg Hg/kg/day) of this compound resulted in hypercoagulation. The reduction of the clotting time, the increase of fibrinogen level in plasma and changes characteristic of hypercoagulation in the thromboelastographic parameters were observed. Simultaneously, signs of impaired activity of blood platelets: decreased aggregation velocity and clot retraction as well as prolongation of the bleeding time were noticed.

Adenosine Diphosphate↗
PubMedDate not supplied

The in vitro effect of methylmercuric chloride on superoxide dismutase activity of pig platelets.

Incubation of the suspension of washed pig platelets with methylmercuric chloride (MeHg) caused decrease of superoxide dismutase (SOD) activity at the concentrations of MeHg 10(-5)-10(-4) mol/l. We also observed the increase of enzyme activity at low concentrations of MeHg (10(-7)-10(-6) mol/l). MeHg affects the SOD activity similarly to other mercurials which are known to react with sulfhydryl groups, and differentially influence enzymatic systems.

Animals↗