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The study objective was to test the hypothesis that simvastatin and fenofibrate should cause an increase in butyrylcholinesterase (BuChE) activity not only in the plasma and liver but also in the brain of normolipidemic and hyperlipidemic rats. Catalytic enzyme activity was measured using acetylthiocholine (ATCh) and butyrylthiocholine (BTCh) as substrates. Normolipidemic and hyperlipidemic rats were divided in four groups receiving 50 mg/kg of simvastatin a day or 30 mg/kg of fenofibrate a day for three weeks and three control groups receiving saline. Simvastatin and fenofibrate caused an increase in brain BuChE activity in both normo- and hyperlipidemic rats regardless of the substrate. The increase with BTCh as substrate was significant and practically the same in normolipidemic and hyperlipidemic rats after simvastatin treatment (14–17% vs controls). Simvastatin and fenofibrate also increased liver and plasma BuChE activity in both normolipidemic and hyperlipidemic rats regardless of the substrate. In most cases the increase was significant. Considering the important role of BuChE in cholinergic transmission as well as its pharmacological function, it is necessary to continue investigations of the effects of lipid-lowering drugs on BuChE activity., Cilj ispitivanja bio je u normolipidemičnih i hiperlipidemičnih štakora potvrditi pretpostavku da simvastatin (SIMV) I fenofibrat (FENO) ne uzrokuju samo povećanje aktivnosti butirilkolinesteraze (BuChE) u plazmi i jetri nego i povećavaju aktivnosti BuChE u mozgu. Katalitička aktivnost enzima mjerena je upotrebom acetiltiokolina (ATCh) i butiriltiokolina (BTCh) kao supstrata. Normolipidemični i hiperlipidemični štakori raspoređeni su u eksperimentalne skupine, koje su tri tjedna primale SIMV 50 mg/kg na dan ili FENO 30 mg/kg na dan, dok su kontrolne skupine primale fiziološku otopinu. I SIMV i FENO uglavnom su izazvali povećanje aktivnosti BuChE u mozgu obaju sojeva štakora bez obzira na korišteni supstrat. Aktivnosti BuChE mjerene BTCh kao supstratom bile su značajno veće u odnosu na kontrolne vrijednosti u mozgu normolipidemičih štakora nakon primjene SIMV te u mozgu hiperlipidemičnih štakora nakon primjene obaju agensa (14‒17%, p<0,001). Povećanje aktivnosti BuChE u plazmi i jetri nakon primjene SIMV i FENO izmjeren je u oba soja štakora bez obzira na to je li korišten ACTh ili BTCh. U većini slučajeva povećanje aktivnosti BuChE u plazmi i jetri bilo je značajno. S obzirom na važnu ulogu BuChE u kolinergičnom prijenosu te na njezinu farmakološku funkciju, potrebno je nastaviti istraživanja utjecaja antilipidnih lijekova na aktivnost BuChE.

U radu je ispitivan utjecaj pet eteričnih ulja (anisa, paprene metvice, bosiljka, ružmarina i lavande prave) i njihovih dviju najzastupljenijih komponenti na porast micelija Colletotrichum coccodes, ekonomski značajne fitopatogene gljive i uspoređen s fungicidima. Ispitivanja su provedena u uvjetima in vitro u osam volumena na PDA podlozi u četiri ponavljanja. Porast micelija mjeren je osmi i petnaesti dan nakon nacjepljivanja micelija. Utvrđeno je da neka eterična ulja i komponente, primijenjeni u određenome volumenu, imaju signifikantan antifugalni učinak, u pojedinim primjerima usporediv s fungicidima. Najbolje djelovanje i najniži IC50 imala su eterična ulja anisa i paprene metvice te komponenta anetol. Petnaesti dan nakon inokulacije micelija eterična ulja imala su značajno bolje antifungalno djelovanje od svoje druge komponente po zastupljenosti., The effect of five essential oils (anise, peppermint, basil, rosemary and true lavander) and their two most common components on the mycelial growth in Colletotrichum coccodes, economically important phytopathogic fungi and compared with fungicides have been investigated in the study. Tests were conducted in vitro conditions in eight volumes on a PDA substrate in four replicates. The increase in mycelium was measured on the eighth and fifteenth day after the mycelium inoculation. It was found out that some essential oils and components applied at a given volume have a significant antifungal effect, in some examples comparable to fungicides. Anise and peppermint essential oils as well as the anethole component had the best activity and the lowest IC50. Fifteen days after the inoculation of the mycelium, the essential oils had a significantly better antifungal activity compared to their second most represented component.

The pathogenesis of recurrent urinary tract infections (UTIs) in preschool children with anatomically correct urinary tract (UT) is rather obscure. In girls, the bladder wall changes of cystitis cystica (CC) may be per se responsible for UTIs recurrence. During the 20-year period, 127 preschool children (125 girls; median age: 6.1 years) with CC, in whom UT anomalies were excluded, were diagnosed. The mean duration of UTIs symptoms prior to diagnosis was 3.31±2.51 years. Cystoscopical findings were labelled as mild, moderate and severe in 22.8%, 39.4% and 37.8% of patients, respectively. Following the confirmation of CC, long-term chemoprophylaxis with sulfamethoxazole-trimethoprim/nitrofurantoin was administered. A one year UTI-free period after chemoprophylaxis discontinuation was defined as therapeutic success. With 2.5 years median duration of regular chemoprophylaxis this goal was achieved in 58 children mainly with mild/ moderate CC. Thirty children from »improved/unchanged« group taking regular prophylaxis had significant reduction of UTIs (»improved«). Only 12 children belonging to the same group taking regular prophylaxis and all children with irregular prophylaxis had approximately the same number of UTIs as before treatment (»unchanged«). The »improved/unchanged« outcomes were predominantly found in children with severe form of CC. Although urodynamic disturbances detected in more than 50% of patients in whom urodynamics was performed were not found influential on the disease outcome, they could be responsible for its development. The results of our study suggest that regular and long-lasting chemoprophylaxis remains a basis for successful treatment for majority of patients with CC, even those with severe forms. If not treated properly with chemoprophylactic agents and without fair compliance in taking drugs, the disease is prone to recurrent UTIs.

The etiology of recurrent spontaneous abortion (RSA) is still unexplained. Many couples do not find the cause of their RSA at all. The purpose of this research was to evaluate the association between recurrent pregnancy loss and previous (cured prior to pregnancy) acute/chronic genitourinary infections in both parents. Couples (226) having two or more (up to six) spontaneous abortions were analyzed in this retrospective case-control study. The control group consisted of 124 couples with neither miscarriages nor complicated pregnancies in their past. The data (serum immunological markers, karyotype, flow cytometry data, PHD) were collected from their medical charts. It was found that there was no statistically significant difference in average weeks of pregnancy in which the second, third and fourth abortion occurred. There was a statistically significant difference in previously experienced genitourinary infections between women from the RSA group and the control group, as well as for men from the RSA group and the control group. It can be concluded that past infections of the maternal and/or paternal genitourinary system may be the causal factor for recurrent pregnancy loss and can also pre-determine women that are of greater susceptibility to preterm pregnancy. Therefore the genetic counseling of couples should include thorough medical and family history of both partners and their first- and second-degree relatives in conjunction with typical medical examination.

The model of ICAM-1 and LFA-1 molecular interaction was used to test the application of the Molecular Recognition Theory for the identification of several discontinuous binding regions, i.e. ligand-receptor sites, within large antigenic molecules. Molecular Recognition Theory is an applicable heuristic algorithm for identification of possibly interacting amino acid pairs in short linear epitope/paratope sites within larger molecules. However, in order to achieve better efficiency this heuristic algorithm of molecular recognition has to be combined to several other procedures: molecular hydropathy analyses, secondary structure prediction methods and protein database search. The limitation of the combined MRT-hydropathy analyses is in the fact that it cannot explain 3D protein interactions, but it can be a valuable starting point for a more complex computational and experimental analysis.

Prostaglandin (PGE2 and PGI2) synthesis was determined in the cerebrospinal fluid (CSF) and serum of 19 hypoxic neonates at the age of 5–96 hours by using Enzyme Linked Immunosorbent Assay (ELISA) method. Control group consisted of 8 children of the same age whose samples were taken due to initial suspicion of neonatal meningitis. The prostaglandin concentrations in CSF were correlated with initial hypoxic-ischemic encephalopathy (HIE) stage and neurological findings of patients at the age of 12 months. The values of PGE2 and PGI2 in the CSF of children with perinatal hypoxia (PNH) were significantly higher than in the children from the control group. The values of PGI2 in serum were significantly higher than in »CSF« of patients with PNH. Although average values of PGE2 and PGI2 in the liquor were higher in children with advanced stage of HIE, the differences between different stages were not statistically significant. We did not find any significant correlation between average concentrations of prostaglandins and neurological findings of the 12-month-old children.

The hydropathic profile, secondary structure, epitope and binding site of the a-melanotropin molecule were investigated. It was shown that the standard algorithm according to Kyte and Doolittle may be combined with complex methods of the secondary structure prediction to extract the information relevant for the epitope location and modeling. The binding ligand-receptor motifs of the hormone were investigated by means of the SSpro8 method. The Molecular Recognition Theory combined with an NCBInr protein database search was applied to find the possible paratope (receptor) structures for the predicted a-melanotropin epitope (ligand). The described concept constitutes a useful and simple set of procedures for deriving new biologically active peptides and antibodies and also for performing modulation of peptide-receptor interaction.

We evaluated the effectiveness of latanoprost (Xalatan™) monotherapy in primary open angle glaucoma (POAG). Latanoprost is a prostaglandin analogue, the pure 15® epimer of 13,14-dihydro-17-phenyl-18,19,20-trinor-PGF2α- isopropyl ester. As a prodrug it is being activated by enzymatic hydrolysis in the cornea after which it becomes active acid of latanoprost. Latanoprost is lowering the intraocular pressure (IOP) by increasing the uveoscleral outflow. In this study, latanoprost was used once daily as monotherapy what offers much better compliance for the patients than other combinations of drugs, preserving good IOP control. Based on the significant reduction of the IOP, measured on the day 60 of the trial (mean change in IOP was –5.1 mmHg, with 95% confidence interval in range from –5.6 to –4.5), it is concluded that use of latanoprost is advisable when calculating better IOP control, few side-effects and reductions in costs of potential surgical procedures.

Large scale preparation of N-1-sulfonylcytosine derivatives has been optimized. The best method was the condensation reaction of silylated cytosine (1) with p-toluenesulfonyl chloride in acetonitrile. Depending on the isolation procedure, 1-(p-toluenesulfonyl)cytosine 2 and 1-(p- -toluenesulfonyl)cytosine hydrochloride 3 were isolated in 80 % and 75 % yields, respectively. The NMR evidence presented shows that 2 appears as a common keto-amino tautomer in DMSO-d6 solution while its hydrochloride 3 forms exclusively the rare keto imino tautomer. N-1-Sulfonylcytosine derivatives 2 and 3 were investigated for possible cytotoxic activity on human normal fibroblasts (WI38), human pancreatic adenocarcinoma cells (MIAPaCa2), poorly differentiated cells from lymph node metastases of colon carcinoma (SW-620), and human Burkitt lymphoma cells (Raji). MTT-cytotoxicity screens in human tissue culture cell lines showed that both investigated compounds demonstrated antiproliferative activity in different histological types of tumors. In comparison with 5-fluorouracil, some of N-1-sulfonylcytosine derivatives showed 10 times stronger activity, with respect IC50. The inhibitory effect of the investigated derivatives on normal human cells was lower compared to their antitumor effects. In addition to antitumor effects, hematological findings following the parenteral administration of substances were also investigated., Optimizirana je priprava većih količina N-1-sulfonilcitozinskih derivata, kondenzacijom sililiranoga citozina i p-toluensulfonil klorida u acetonitrilu. Ovisno o načinu izolacije dobiveni su 1-(p-toluensulfonil)citozin 2 (80 %) i 1-(p-toluensulfonil)citozin hidroklorid 3 (75 %). NMR eksperimenti pokazuju isključivo nastajanje keto-imino tautomera 3 u DMSO-d6 otopini, dok se 2 pojavljuje u uobičajenome keto-amino obliku. Ispitivani su potencijalni citotoksični učinci N-1-sulfonilcitozinskih derivata 2 i 3 na fibroblastima čovjeka (WI38), stanicama adenokarcinoma gušterače (MIAPaCa2), slabo diferenciranim metastazama adenokarcinoma debelog crijeva (SW-620) i stanicama Burkitt-ovog limfoma (Raji). Rezultati dobiveni MTT-testom pokazuju da ispitivani spojevi djeluju antiproliferativno na različite histološke tipove tumora. U usporedbi s 5-fluorouracilom, N-1-sulfonilcitozinski derivati pokazuju 10 puta jaču inhibiciju rasta izloženih tumorskih stanica. Inhibicijski učinci ispitivanih spojeva na normalne stanice značajno su slabiji u odnosu na protutumorske učinke. Osim antitumorskoga učinka, ispitivani su i hematološki parametri poslije parenteralne primjene ispitivanih tvari.

We investigated the effects of the neuropeptide met-enkephalin on histamine-induced bronhoconstriction in an experimental model of asthma. Classic Konzett and Rössler’s method of whole body plethysmography modified by Gjuriš, was applied in the study. This method represents a standard experimental model of bronchoconstriction, suitable for the evaluation of peptide effects on the histamine-induced bronchoconstriction. The results of the measurements implicate a dose-related modulatory effect of met-enkephalin on the bronchoconstrictor action of histamine. Met-enkephalin doses of 1 mg/kg and 10 mg/kg, respectively, caused statistically significant reduction of the histamine-induced bronchoconstriction. Estimated ED50 dose was 0.235 mg/kg. Further studies are needed to define practical and therapeutical use of the presented observations in respiratory pharmacology.

We describe new binary algorithm for the prediction of α and β protein folding types from RNA, DNA and amino acid sequences. The method enables quick, simple and accurate prediction of α and β protein folds on a personal computer by means of a few binary patterns of coded amino acid and nucleotide physicochemical properties. The algorithm was tested with machine learning SMO (sequential minimal optimization) classifier for the support vector machines and classification trees, on a dataset of 140 dissimilar protein folds. Depending on the method of testing, the overall classification accuracy was 91.43% – 100% and the tenfold cross-validation result of the procedure was 83.57% – >90%. Genetic code randomization analysis based on 100,000 different codes tested for the protein fold prediction quality indicated that: a) there is a very low chance of p = 2.7 x 10^(-4) that a better code than the natural one specified by the binary coding algorithm is randomly produced, b)dipeptides represent basic protein units with respect to the natural genetic code defining of the secondary protein structure.

Maximal plasma creatine kinase (CPK) values are often used as an enzymatic test in acute myocardial infarction. The cardiovascular functional ability (FA) is a reliable parameter, which may define the lesion of the cardiovascular system following myocardial infarction. We have applied the Cubist machine learning tool to set up a model that defines the residual cardiovascular functional ability after a myocardial infarction by means of the maximal CPK in the acute phase of the disease. Cubist models numeric data and generates values by means of a collection of rules associated with the linear expression for computing target values. Based on the literature data set of Mirić et al.,1 we have derived and tested a reliable and accurate Cubist model for acute inferior and anteroseptal myocardial infarction consisting of three simple rules. The rules enable simple prediction of the expected cardiovascular functional ability in myocardial infarction following recovery. The model is based on two clinical parameters related to the disease, maximal CPK in the acute phase of the myocardial lesion, and anteroseptal or inferior cardial localisation of the infarction. Strong correlation (r anteroseptal = 1.00, r inferior = 0.94, n = 56), insignificant differences of real and predicted values, and low average error of the leave-one-out test (anteroseptal 1.72, inferior 3.54) confirm the accuracy of the method and its applicability in clinical medicine. In addition to the prognostic and diagnostic application, the extracted rules enable more efficient evaluation of new drugs and therapeutic procedures in Cardiology.

Dialysis related amyloidosis is the accumulation and deposition of P2-microglobulin derived fibrils in bones and joints, due to insufficient elimination during therapy or slowly progressing renal failure. The aim of this Study was to analyse biochemical, morphologic and anamnestic parameters that may be relevant for the onset and developement of dialysis related amyloidosis. In addition to standard statistical procedures, we also applied the machine-learning based methods of data mining to quantify the risk factors for asymptomatic patients. Extraction of risk factors for the onset of the dialysis related amyloidosis syndrome could enable the clinician to predict the symptoms and consider medical procedures to prevent the onset of the disease. The C4.5 machine learning algorithm extracted a simple and highly accurate tree for discrimination of asymptomatic and symptomatic patients suffering from dialysis related amyloidosis. It remains an open question if our findings may contribute to the problem of accurately predicting the onset of dialysis related arthropathy in the asymptomatic patient group.

Dialysis related amyloidosis is the accumulation and deposition of P2-microglobulin derived fibrils in bones and joints, due to insufficient elimination during therapy or slowly progressing renal failure. The aim of this Study was to analyse biochemical, morphologic and anamnestic parameters that may be relevant for the onset and developement of dialysis related amyloidosis. In addition to standard statistical procedures, we also applied the machine-learning based methods of data mining to quantify the risk factors for asymptomatic patients. Extraction of risk factors for the onset of the dialysis related amyloidosis syndrome could enable the clinician to predict the symptoms and consider medical procedures to prevent the onset of the disease. The C4.5 machine learning algorithm extracted a simple and highly accurate tree for discrimination of asymptomatic and symptomatic patients suffering from dialysis related amyloidosis. It remains an open question if our findings may contribute to the problem of accurately predicting the onset of dialysis related arthropathy in the asymptomatic patient group.

Maximal plasma creatine kinase (CPK) values are often used as an enzymatic test in acute myocardial infarction. The cardiovascular functional ability (FA) is a reliable parameter, which may define the lesion of the cardiovascular system following myocardial infarction. We have applied the Cubist machine learning tool to set up a model that defines the residual cardiovascular functional ability after a myocardial infarction by means of the maximal CPK in the acute phase of the disease. Cubist models numeric data and generates values by means of a collection of rules associated with the linear expression for computing target values. Based on the literature data set of Mirić et al.,1 we have derived and tested a reliable and accurate Cubist model for acute inferior and anteroseptal myocardial infarction consisting of three simple rules. The rules enable simple prediction of the expected cardiovascular functional ability in myocardial infarction following recovery. The model is based on two clinical parameters related to the disease, maximal CPK in the acute phase of the myocardial lesion, and anteroseptal or inferior cardial localisation of the infarction. Strong correlation (r anteroseptal = 1.00, r inferior = 0.94, n = 56), insignificant differences of real and predicted values, and low average error of the leave-one-out test (anteroseptal 1.72, inferior 3.54) confirm the accuracy of the method and its applicability in clinical medicine. In addition to the prognostic and diagnostic application, the extracted rules enable more efficient evaluation of new drugs and therapeutic procedures in Cardiology.

The model of ethanol induced gastric lesions is useful in the evaluation of gastric cytoprotection. We used it to measure cytoprotective effects of two neuropeptides, Met-enkephalin (Peptid-M, LUPEX®) and α-melanocyte stimulating hormone (α-MSH). Both peptides exhibited significant and synergistic cytoprotective effects. The best therapeutic efficacy was obtained with Met-enkephalin and α-MSH mixture 3-5 : 1. Significant cytoprotective action on ethanol induced lesions was also observed by means of two thymus peptide immunomodulators, Thymus Peptide C® and JAN 50®. Thymus Peptide C® exhibited a more significant synergistic effect with Met-enkephalin than JAN 50®. In addition to the cytoprotection of rat gastric mucosa, Met-enkephalin also induced statistically significant and dose dependent Straub tail response versus control in miče. Haloperidol, naloxone and Peptide-D antagonised its effects. NMR spectrospic data supported molecular interaction of Met-enkephalin and haloperidol, while neutralization of Met-enkephalin induced Straub tail response by means of Peptide-D indicated the presence of new non-opioid (naloxone independent) receptor system containing Peptide-D sequence (calpastatin 201-205 aa).

We applied the machine learning procedure to the analysis of serum and aqueous humor albumin, IgG and interferon-γ patterns. The data were analyzed with respect to the cataract, type of diabetes, retinopathy and blood-aqueous humor barrier damage. Intraocular production of IgG was detected in diabetic patients, since the IgG index values were increased in some diabetic groups (especially those with type I diabetes and retinopathy). Comparison of numerical methods and clonal IgG detection suggested that intraocular IgG patterns in diabetes are predominately polyclonal. Interferon-γ (IFN-γ) was pathological in serum and aqueous humor of patients with type I diabetes and to a lesser extent in the type II diabetes group. Machine learning system based on C5.0 classifier extracted 98.5% accurate rules for discrimination of the senile cataract group, diabetes group and diabetic retinopathy group. Our results confirm that the combination of immunochemical and numerical methods with a proper statistical analysis may contribute to the diagnosis of the pathologic ocular immune response and the related retinal or vascular disorders in diabetes. Significant savings in laboratory material and efforts may be obtained by means of the machine learning based optimization of the tests.

The model of ethanol induced gastric lesions is useful in the evaluation of gastric cytoprotection. We used it to measure cytoprotective effects of two neuropeptides, Met-enkephalin (Peptid-M, LUPEX®) and α-melanocyte stimulating hormone (α-MSH). Both peptides exhibited significant and synergistic cytoprotective effects. The best therapeutic efficacy was obtained with Met-enkephalin and α-MSH mixture 3-5 : 1. Significant cytoprotective action on ethanol induced lesions was also observed by means of two thymus peptide immunomodulators, Thymus Peptide C® and JAN 50®. Thymus Peptide C® exhibited a more significant synergistic effect with Met-enkephalin than JAN 50®. In addition to the cytoprotection of rat gastric mucosa, Met-enkephalin also induced statistically significant and dose dependent Straub tail response versus control in miče. Haloperidol, naloxone and Peptide-D antagonised its effects. NMR spectrospic data supported molecular interaction of Met-enkephalin and haloperidol, while neutralization of Met-enkephalin induced Straub tail response by means of Peptide-D indicated the presence of new non-opioid (naloxone independent) receptor system containing Peptide-D sequence (calpastatin 201-205 aa).

We applied the machine learning procedure to the analysis of serum and aqueous humor albumin, IgG and interferon-γ patterns. The data were analyzed with respect to the cataract, type of diabetes, retinopathy and blood-aqueous humor barrier damage. Intraocular production of IgG was detected in diabetic patients, since the IgG index values were increased in some diabetic groups (especially those with type I diabetes and retinopathy). Comparison of numerical methods and clonal IgG detection suggested that intraocular IgG patterns in diabetes are predominately polyclonal. Interferon-γ (IFN-γ) was pathological in serum and aqueous humor of patients with type I diabetes and to a lesser extent in the type II diabetes group. Machine learning system based on C5.0 classifier extracted 98.5% accurate rules for discrimination of the senile cataract group, diabetes group and diabetic retinopathy group. Our results confirm that the combination of immunochemical and numerical methods with a proper statistical analysis may contribute to the diagnosis of the pathologic ocular immune response and the related retinal or vascular disorders in diabetes. Significant savings in laboratory material and efforts may be obtained by means of the machine learning based optimization of the tests.

The structure, complementary structure and cytogenetic/proliferative effects of the Met-enkephalin on human peripheral blood lymphocytes were analyzed. Met-enkephalin, i.e. Peptid-M (LUPEX®), is a low molecular weight synthetic pentapeptide that corresponds to thymus Met-enkephalin. Its structure was examined by means of NMR spectroscopy. The influence of Met-enkephalin on in vitro normalization of chromosomally aberrant lymphocytes of patients suffering from different immune-mediated diseases, was analyzed by the sensitive cytogenetic tests for screening and detection of genome damages in human lymphocytes. The tests showed that in vitro stimulation of human lymphocytes with the Met-enkephalin led to dissapearance of different types of chromosome aberrations, reduction in the number of micronuclei, decrease in the frequency of sister chromatid exchange (SCE) and apoptosis as well as a cytostatic effect on mitosis cycles. They have also confirmed normalization of chromosomally aberrant cell findings in patients suffering from different immune-mediated diseases. These results suggest a possible role of Met-enkephalin (Peptid-M) in immunotherapy of different diseases which involve chromosomal aberrations as well as abnormal cell proliferation and offer new approaches to immunotherapy by the use of Peptid-M. Based on the molecular recognition theory and the SCA method, peptide complementary to Peptid-M was designed, synthesized and denoted Peptide-D. Peptide-D is a calpastatin fragment. Predicted ligand-receptor interaction between both peptides is confirmed by the results showing that Peptide-D blocked the Peptid-M induced lymphocyte proliferation in a dosedependent manner.

The structure, complementary structure and cytogenetic/proliferative effects of the Met-enkephalin on human peripheral blood lymphocytes were analyzed. Met-enkephalin, i.e. Peptid-M (LUPEX®), is a low molecular weight synthetic pentapeptide that corresponds to thymus Met-enkephalin. Its structure was examined by means of NMR spectroscopy. The influence of Met-enkephalin on in vitro normalization of chromosomally aberrant lymphocytes of patients suffering from different immune-mediated diseases, was analyzed by the sensitive cytogenetic tests for screening and detection of genome damages in human lymphocytes. The tests showed that in vitro stimulation of human lymphocytes with the Met-enkephalin led to dissapearance of different types of chromosome aberrations, reduction in the number of micronuclei, decrease in the frequency of sister chromatid exchange (SCE) and apoptosis as well as a cytostatic effect on mitosis cycles. They have also confirmed normalization of chromosomally aberrant cell findings in patients suffering from different immune-mediated diseases. These results suggest a possible role of Met-enkephalin (Peptid-M) in immunotherapy of different diseases which involve chromosomal aberrations as well as abnormal cell proliferation and offer new approaches to immunotherapy by the use of Peptid-M. Based on the molecular recognition theory and the SCA method, peptide complementary to Peptid-M was designed, synthesized and denoted Peptide-D. Peptide-D is a calpastatin fragment. Predicted ligand-receptor interaction between both peptides is confirmed by the results showing that Peptide-D blocked the Peptid-M induced lymphocyte proliferation in a dosedependent manner.