Biological therapies in the prevention of maternal mortality.

Although the maternal mortality rate has decreased and significant improvements have been made in maternal care, maternal death remains one of the substantial problems of our society. The leading causes of maternal death are postpartum hemorrhage, the most important cause of death in developing countries, and preeclampsia and venous thromboembolism, which are more prevalent in developed countries. To treat these conditions, a variety of therapeutic approaches, including pharmacologic agents and surgical techniques, have been adopted. However, a certain number of pregnant women do not respond to any of these options. That is the main reason for developing new therapeutic approaches. Biological medications are isolated from natural sources or produced by biotechnology methods. Heparin is already successfully used in the therapy of deep venous thrombosis and pulmonary embolism. Blood derivatives, used in an autologous or allogenic manner, have proven to be efficacious in achieving hemostasis in postpartum hemorrhage. Mesenchymal stem cells, alpha-1-microglobulin, and antithrombin exhibit promising results in the treatment of preeclampsia in experimental models. However, it is essential to evaluate these novel approaches' efficacy and safety profile throughout clinical trials before they can become a standard part of patient care.

Protective effect of olive leaf extract on hippocampal injury induced by transient global cerebral ischemia and reperfusion in Mongolian gerbils.

The beneficial effects of antioxidant nutrients, as well as complex plant extracts, in cerebral ischemia/reperfusion brain injury are well known. Mediterranean diet, rich in olive products, is associated with lower incidence of cardiovascular disease, cancer, inflammation and stroke. In this study, the possible neuroprotective effect of standardized dry olive leaf extract (OLE) is investigated for the first time. Transient global cerebral ischemia in Mongolian gerbils was used to investigate the OLE effects on different parameters of oxidative stress and neuronal damage in hippocampus. The biochemical measurements took place at different time points (80min, 2, 4 and 24h) after reperfusion. The effects of applied OLE were compared with effects of quercetin, a known neuroprotective plant flavonoid. Pretreatment with OLE (100mg/kg, per os) significantly inhibited production of superoxide and nitric oxide, decreased lipid peroxidation, and increased superoxide dismutase activity in all time points examined. Furthermore, OLE offered histological improvement as seen by decreasing neuronal damage in CA1 region of hippocampus. The effects of applied OLE were significantly higher than effects of quercetin (100mg/kg, per os). Our results indicate that OLE exerts a potent neuroprotective activity against neuronal damage in hippocampus after transient global cerebral ischemia, which could be attributed to its antioxidative properties.

Attenuation of cold restraint stress-induced gastric lesions by an olive leaf extract.

Olive leaf extract (OLE) possesses, among other, antioxidative properties, but whether it influences gastroprotection against stress-induced gastric lesions remains unknown. In this study we investigated the protective effect of OLE, a natural antioxidant, on gastric mucosal damage induced by cold restraint stress (CRS) in rats. Three different doses of commercial OLE EFLA((R)) 943 were applied intragastrically (i.g.) 30 min prior to stress induction. Macroscopic gastric lesions were evaluated and ulcer index (UI) was calculated. Histological evidence of gastric mucosal lesions was also obtained. Concentration of malondialdehyde (MDA) as an index of lipid peroxidation, and catalase (CAT) and superoxide dismutase (SOD) activities were determined in gastric mucosa. The effects of applied OLE on gastric mucosal lesions, lipid peroxidation and antioxidative enzymes activity were compared with effects of i.g. pretreatment of reference drug, ranitidine. CRS caused severe gastric lesions in all non-pretreated animals, and this finding was confirmed histologicaly. Pretreatment with OLE (40, 80 and 120 mg.kg(-1)), as well as with ranitidine (50 mg.kg(-1)), significantly (p < 0.001) attenuated stress-induced gastric lesions. Treatment with 80 mg.kg(-1) of OLE was the most effective in prevention of rise in gastric MDA level and decrease in CAT and SOD activity. The results obtained indicate that OLE possesses gastroprotective activity against CRS-induced gastric lesions in rats, possibly related to its antioxidative properties.

Plasma homocysteine levels in young male patients in the exacerbation and remission phase of schizophrenia.

High levels of homocysteine (Hcy) were suggested to contribute to the pathogenesis of schizophrenia. Recent investigations have shown that treatment with folic acid, vitamin B-12 and pyridoxine are effective in reducing Hcy levels while concomitantly reducing the score of positive and negative symptoms in schizophrenic patients. In addition to the availability of nutrients (mainly folate, vitamins B6 and B12), plasma Hcy concentrations are dependent on complex metabolic regulation that could be disrupted in schizophrenia. This study was designed to test the influence of disease activity on plasma Hcy levels. Plasma Hcy concentrations were measured in male chronic schizophrenic patients with a predominantly positive (SCH (+)) or predominantly negative (SCH (-)) syndrome in schizophrenia immediately upon admission to the hospital (exacerbation phase) and one month later (remission phase). During this period patients received antipsychotic medications without vitamin therapy. The effects of age, duration of illness, folate and B12 concentrations, as well as smoking and coffee consumption habits on the observed changes were evaluated. Age- and sex-matched subjects were included in the control group. In the control group plasma Hcy concentration was 8.75+/-1.84 micromol/L. In the exacerbation phase plasma Hcy concentrations were significantly increased both in SCH (+) (14.91+/-6.19 micromol/L) and SCH (-) groups (12.8+/-3.27 micromol/L). There was no difference in plasma Hcy concentrations between SCH (+) and SCH (-) patients. Serum folate and B12 concentrations were not significantly different in any of the investigated groups of subjects. The plasma Hcy concentrations could not be correlated with age, duration of illness, the score of positive symptoms or the concentration of folate and vitamin B12. A positive correlation was found between plasma Hcy level and score of negative symptoms in both groups of patients. No correlation was found between smoking or coffee consumption habits and plasma Hcy concentrations. All patients exhibited decreased plasma Hcy levels in the remission phase of the illness, with a mean decrease of 2.68+/-1.57 micromol/L. Folate and B12 levels did not differ in the exacerbation and remission phases of the illness. The significant decrease of plasma Hcy levels, without changes in folate and vitamin B12 concentrations in the remission phase of schizophrenia, could indicate an influence of a pathogenetic process involved in schizophrenia on Hcy metabolism.

Synthesis and biological activity of some new 5'-O-acyl tiazofurin derivatives.

Three new 5'-O-acyl tiazofurin derivatives 2-4 were synthesized and evaluated for their antiproliferative activity against different tumour cell lines as well as for their ability to induce apoptosis in C6 cells in vitro. Apart of the antitumour assays, the cell membrane permeation of 2-4 and their intracellular metabolism in C6 cells in vitro was also studied in order to evaluate their potential as possible tiazofurin bioisosteres or prodrugs.

The effects of tiazofurin on basal and amphetamine-induced motor activity in rats.

The effects of tiazofurin (TR; 2-beta-d-ribofuranosylthiazole-4-carboxamide), a purine nucleoside analogue on basal and amphetamine (AMPH)-induced locomotor and stereotypic activity of adult Wistar rat males were studied. The animals were injected with low (3.75, 7.5, and 15 mg/kg ip) and high (62.5, 125, and 250 mg/kg ip) TR doses. Neither low nor high TR doses influenced basal locomotor and stereotypic activity in comparison with the corresponding controls treated with saline only. However, pretreatment with TR at any dose applied, except for the lowest one, significantly decreased AMPH-induced (1.5 mg/kg ip) locomotor activity, while AMPH-induced stereotypic activity was inhibited with the two highest TR doses. In addition, TR was detected in the brain by HPLC already 15 min after the injection (125 mg/kg ip) to reach a maximum 2 h after the administration and was detectable in this tissue during the next 4 h. Our results indicate that TR modifies central regulation of the motor activity, possibly by influencing dopaminergic (DA-ergic) transmission.

HPLC determination of tiazofurin in the rat brain.

A sensitive, selective and reproducible HPLC method for determination of tiazofurin in rat brain was developed and validated. The method allowed determination and quantification of nanomolar concentrations of tiazofurin in brain and its regions (hippocampus, cortex and striatum) of treated animals. Separation of tiazofurin from other peaks from brain tissue was achieved by isocratic elution on reverse phase chromatographic column. The mobile phase consisted of 0.05 M sodium acetate pH 4.6. Run time was 15 min.

Characterization of 9L glioma model of the Wistar rat.

The aim of our study was to develop and characterize solid brain tumors in Wistar rats, which could be used in investigations concerning the molecular mechanisms that lay beneath the genesis of the gliomas as well as in the testing of curative potentials of various therapeutics. The tumors were induced by intracerebral inoculation of 9L glioma cells and characterized by morphometrical, histological and immunohistochemical analysis after 7, 14 and 21 postimplantation days. Immunohistochemical characterization included detection of the nuclear antigene Ki-67 as the proliferative cell marker, GFAP as a tracer of reactive gliosis surrounding the tumor mass, and CD4/CD8 and ED1 antigens, as markers of the immunological response. Our results showed that after 7 days all experimental animals developed solid, well-circumcised tumors, which were clearly separated from the surrounding brain tissue. Tumors showed progressive growth from the 7th to the 21st day despite the observed immunological response starting after 14 days. Histologically tumors were hypercellular with neovascularization and necrosis. These results indicate that reproducible morphometric evaluation can be performed on 9L tumors growing in immunocompetent Wistar rats, enabling its use as an animal tumor model for the evaluation of various therapeutic approaches.

Synthesis and biological evaluation of some novel 4'-thio-L-ribonucleosides with modified nucleobase moieties.

1,2,3,5-tetra-O-acetyl-4-thio-beta-L-ribofuranose (13) was synthesized by an improved five-step sequence starting from methyl alpha-D-lyxopyranoside. Compound 13 was then converted to the corresponding L-4'-thionucleosides 4-6 and 19 by a modified Vorbrüggen procedure. All of these nucleoside analogues were tested for their antitumour activity in vitro.

Simultaneous LC determination of tiazofurin, its acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide in biological samples.

A rapid and sensitive HPLC-RP method for simultaneous determination of tiazofurin, its 5'-O acetyl and benzoyl esters and their active metabolite thiazole-4-carboxamide adenine dinucleotide was developed and validated. The method allowed determination and quantification of nanomolar quantities of these substances in cell extracts of treated cells, and was also used in kinetic studies of cellular uptake of tiazofurin and its esters from the cultivation medium. Separation of the analyzed substances from unidentified peaks from both biological materials was achieved by gradient elution, thus reducing the possibility of interference. The mobile phase consisted of a 0.1 M sodium-hydrogen phosphate, pH 5.1 and methanol. Run time was 22 min, with 5 min equilibration time.