Dipeptidyl peptidase IV (DPPIV) enzyme activity on immature T-cell line R1.1 is down-regulated by dynorphin-A(1-17) as a non-substrate inhibitor

In this study we examined surface expression of CD26 and the corresponding enzyme activity of dipeptidyl peptidase IV (DPPIV) on the cells of immature murine T-cell line, R1.1. The data obtained have shown that R1.1 cells express high density of surface CD26 as compared to normal thymus cells. This was associated with strong enzyme activity, which, based on substrates and inhibitor specificity, corresponded to DPPIV. The DPPIV enzyme activity of R1.1 cells was 10 times stronger than that found on normal murine thymus cells (V(max) = 39 micromol/min/10(6) cells, vs 3.7 micromol/min/10(6) cells, respectively). Upon activation with anti-CD3, up-regulation of both membrane CD26, as well as of DPPIV enzyme activity on R1.1 cells were observed. The finding of strong DPPIV on R1.1 cells makes them suitable model for testing putative substrates/inhibitors of the enzyme in its natural microenvironment. Since in addition to strong DPPIV, R1.1 cells also express kappa opioid receptors (KOR) [European Journal of Pharmacology 227 (1992) 257], we tested the effect of dynorphin-A(1-17), an endogenous opioid peptide with KOR selectivity, on DPPIV of R1.1 cells. Dynorphin-A(1-17) down-regulated DPPIV in a dose-dependent manner, with the potency similar to that of substance P, a known natural DPPIV substrate [Journal of Pharmacology and Experimental Therapeutics 260 (1992) 1257]. DPPIV down-regulation was resistant to bestatin and thiorphan, the inhibitors of two cell surface peptidases (APN and NEP, respectively) with potential of dynorphin-A(1-17) degradation, suggesting that the mechanism underlying the observed effect does not involve degradative products of dynorphin-A(1-17). DPPIV down-regulation was also resistent to KOR antagonist, NBI, suggesting that the mechanism underlying the observed phenomenon involves neither cointernalization of KOR and DPPIV. Collectively, cells of immature T cell line, R1.1 exert strong DPPIV enzyme activity, which could be down-regulated in the presence of dynorphin-A(1-17) by mechanism that presumably includes non-substrate inhibition. By down-regulating DPPIV, dynorphin-A(1-17) may indirectly affect activity and/or specificity of natural substrates of DPPIV, such as substance P, RANTES, and endomorphins.     

Self-image and refugee status in adolescents from Bosnia and Herzegovina and Croatia

The first aim is focused in refugees comparing them with a comparison group in clinical characteristics. In addition, the authors compared scores on the self-image (S-I) scale of refugees and comparison subjects, after they had stratified them into four groups by gender and age. Subjects were 133 refugees from Bosnia and Herzegovina and comparison subjects were from Zagreb, Croatia (n = 189). The subjects were assessed by psychotherapeutic interview, Offer Self-Image Questionnaire (OSIQ), questionnaires of depressive symptoms, war stressors, posttraumatic reactions (PTS-reactions) and general data. Refugees had significantly higher scores on the questionnaires of war stressors and PTS-reactions (p < 0.001). Refugees didn't differ in the majority of 12 scales of OSIQ from comparison subjects, in all four groups. Younger male refugees had the most scales with significantly higher raw scores in S-I, four in total. S-I can give us useful insight into different dimensions of personality of refugees.     

Ultrasound measurement of the volume of musculus quadriceps after knee joint injury

The monitoring of the recovery of femoral muscles, after the knee-joint injury, is possible by the method of ultrasound measurement of the muscular volume. In a clearly defined longitudinal study, our object was to standardize the method of ultrasound measurement of muscular volume and to evaluate its adequacy in practical application in quadriceps muscle rehabilitation. The ultrasound measurements of m. rectus femoris and m. vastus intermedius were conducted in three intervals: in the first 24 hours after the injury; after 1 week, when immobilization was removed; and after 6 weeks, when rehabilitation was finished. The study comprised 30 patients with knee-joint injury, and 30 asymptomatic subjects, who formed the control group. The results showed significant decrease of muscular volume (mm3) after joint immobilization on injured leg and a significant increase of volume after rehabilitation. The same differences were observed on healthy legs, but without significance. Within the same intervals, there were no changes in the muscular mass in the control group. M. rectus femoris was completely recovered in greater number of patients (54.1%), comparing to m. vastus intermedius (25.4%). We conclude that the ultrasound is an appropriate method for monitoring the process of muscular atrophy during immobilization, as well as the course of muscular restitution during the physical therapy.     

Synthesis and immunostimulating properties of novel adamant-1-yl tripeptides

The aim of this work was to prepare L- and D-(adamant-1-yl)-Gly-L-Ala-D-isoGln peptides in order to study their adjuvant (immunostimulating) activities. Adjuvant activity of adamant-1-yl tripeptides was tested in the mouse model using ovalbumin as an antigen and in comparison to the peptidoglycan monomer (PGM; β-D-GlcNAc-(1→4)-D-MurNAc-L-Ala-D-isoGln-mesoDAP(εNH(2) )-D-Ala-D-Ala) and structurally related adamant-2-yl tripeptides.     

<Emphasis Type="Italic">In vitro</Emphasis> propagation of <Emphasis Type="Italic">Gentiana dinarica</Emphasis> Beck.

Gentiana dinarica Beck, rare and endangered species of Balkan Dinaric alps, was in vitro propagated (micropropagated) from axillary buds of plants collected at Mt. Tara, Serbia. G. dinarica preferred MS to WPM medium, with optimal shoot multiplication on MS medium with 3% sucrose, 1.0 mg l⁻¹ BA and 0.1 mg l⁻¹ NAA. Rooting was not clearly separated from shoot multiplication since BA did not completely inhibit root initiation. Spontaneous rooting on plant growth regulator-free medium occurred in some 30% of shoot explants. Rooting was stimulated mostly by decreased mineral salt nutrition and a medium with 0.5 MS salts, 2% sucrose and 0.5–1.0 mg l⁻¹ IBA was considered to be optimal for rooting. Rooted plantlets were successfully acclimated and further cultured in peat-based substrate.     

Endogenous Auxin Profile in the Christmas Rose (Helleborus niger L.) Flower and Fruit: Free and Amide Conjugated IAA

The reproductive development of the Christmas rose (Helleborus niger L.) is characterized by an uncommon feature in the world of flowering plants: after fertilization the white perianth becomes green and photosynthetically active and persists during fruit development. In the flowers in which fertilization was prevented by emasculation (unfertilized) or entire reproductive organs were removed (depistillated), the elongation of the peduncle was reduced by 20?C30%, and vascular development, particularly lignin deposition in sclerenchyma, was arrested. Chlorophyll accumulation in sepals and their photosynthetic efficacy were up to 80% lower in comparison to fertilized flowers. Endogenous auxins were investigated in floral and fruit tissues and their potential roles in these processes are discussed. Analytical data of free indole-3-acetic acid, indole-3-ethanol (IEt), and seven amino acid conjugates were afforded by LC-MS/MS in floral tissues of fertilized as well as unfertilized and depistillated flowers. Among amino acid conjugates, novel ones with Val, Gly, and Phe were identified and quantified in the anthers, and in the fruit during development. Reproductive organs before fertilization followed by developing fruit at post-anthesis were the main source of auxin. Tissues of unfertilized and depistillated flowers accumulated significantly lower levels of auxin. Upon depistillation, auxin content in the peduncle and sepal was decreased to 4 and 45%, respectively, in comparison to fruit-bearing flowers. This study suggests that auxin arising in developing fruit may participate, in part, in the coordination of the Christmas rose peduncle elongation and its vascular development.     

Xanthatin and xanthinosin from the burs of Xanthium strumarium L. as potential anticancer agents

Xanthatin and xanthinosin, 2 sesquiterpene lactones isolated from the burs of Xanthiun strumarium L. (cocklebur), showed moderate to high in vitro cytotoxic activity in the human cancer cell lines WiDr ATCC (colon), MDA-MB-231 ATCC (breast), and NCI-417 (lung). Xanthatin and xanthinosin were purified as the result of a multi-screening bioassay-guided study of wild plant species of the family Asteraceae, collected from various sites in Saskatchewan, Canada. Seventy-five extracts at a single concentration of 100 microg/mL were evaluated for in vitro cytotoxicity to the human cancer cell lines used. The chloroform extract of Carduus nutans L. (nodding thistle) aerial parts (IC50, 9.3 microg/mL) and the hexane extract of Echinacea angustifolia DC. (narrow-leaved purple coneflower) root (IC50, 4.0 microg/mL) were moderately to highly cytotoxic to the lung cancer cell line. The chloroform extracts of X. strumarium L. burs and Tanacetum vulgare L. (tansy) aerial parts exhibited the highest cytotoxicity for all cell lines tested; their IC50 values, obtained from multidose testing, ranged from 0.1 to 6.2 microg/mL (X. strumarium) and from 2.4 to 9.1 microg/mL (T. vulgare). Further purification of the chloroform fraction of X. strumarium yielded xanthatin and xanthinosin in high yields. This is the first time that these compounds have been reported in the burs of X. strumarium. Their IC50 values are also reported herein.     

A comparative study of the effects of molsidomine and 3-morpholinosydnonimine on the redox status of rat erythrocytes and reticulocytes

After enzymic biotransformation, molsidomine (MO) acts via the metabolite 3-morpholinosydnonimine (SIN-1) through spontaneous liberation of nitric oxide (NO) and superoxide (O(2)(.-)). The aim of this study was to compare the effects of MO and its active metabolite SIN-1 on the redox status of rat erythrocytes and reticulocytes. Rat erythrocyte as well as reticulocyte-rich red blood cell (RBC) suspensions were aerobically incubated (2 h, 37 degrees C) without (control) or in the presence of different concentrations of MO or SIN-1. In rat erythrocytes, biotransformation of MO resulted in the production of NO and nitroxyl (NO(-)). Endogenous superoxide anion (O(2)(.-)) participated in peroxynitrite generation. SIN-1 simultaneously liberated NO and O(2)(.-), which formed peroxynitrite (at least in part), but the liberated NO predominantly reacted with haemoglobin, forming methaemoglobin in erythrocytes. In reticulocytes, MO and SIN-1 caused an increase in the levels of both nitrite and 3-nitrotyrosine (an indicator of peroxynitrite), whereas they decreased the level of O(2)(.-). In reticulocytes, MO was metabolized into SIN-1 which led to the generation of NO, which reacted with O(2)(.-) (endogenous or exogenous) forming reactive nitrogen species. In conclusion, there are two metabolic pathways for MO biotransformation: one causing NO and NO(-) generation predominantly in erythrocytes and the other, via SIN-1 metabolism, in reticulocytes. The main difference between the action of MO and SIN-1 was that the latter caused oxidative damage in RBCs.