112 research outputs found
Jedinjenja prirodnog porekla koja stvaraju zavisnost - narkomanija
The term addiction is used in many contexts. It is not limited to substance abuse and can be applied to any activity characterized by compulsion, loss of control and continuation of the substance despite harm. Some researchers speak of two types of addictions: substance addictions (for example, alcoholism, drug abuse, and smoking); and process addictions (for example, gambling, spending, shopping, eating, and sexual activity). There is a growing recognition that many addicts, such as poly-drug abusers, are addicted to more than one substance or process. It has been shown that individuals turn to substance abuse that elicit a mood or level of arousal consistent with their mode of dealing with stress. Those who deal with stress by confrontation choose drug stimulants. Those who withdrawal from stress choose opiate drugs. Others who deal with stress through activities related to imagery or fantasy turn to hallucinogens. These relationships between behaviour and drug preference are thought to be biochemicaly driven. The biological mechanism of addiction is defined by Milkman. Milkman (1983) defines addiction as 'self-induced changes in neurotransmission that result in social problem behaviours'. This definition encompasses the psychological, biochemical and social aspects of addictive processes. Neurotransmission is the basis for biochemical activity. Small molecules known as neurotransmitters are released into the synaptic junction from the pre-synaptic terminal. After they are released, the neurotransmitters can be degraded by enzymes or be integrated into the post-synaptic membrane and activate adenylate cyclase. This enzyme converts adenosine triphosphate (ATP) into cyclic adenosine-monophosphate (cAMP). cAMP has the effect of increasing membrane sensitivity and subsequent neurotransmission. According to their ability to change the rate of neurotransmission all substances are classified to: stimulant (drugs that increase behavioural activity: amphetamines, methamphetamine, cocaine, nicotine); depressant (alcohol, heroin, morphine, cannabis, barbiturates) and hallucinogen (group of psychoactive chemical compounds which can produce visual or auditory hallucinations). Once a change in neurotransmission is brought about the brain attempts to re-establish the rate of neurotransmission that was present before the activity or substance intake. Once the rate is re-established, the individual becomes tolerant to the original level of the substance. There are two kinds of tolerance: metabolic and cellular. Metabolic tolerance reflects an individual's increased ability to metabolize the drug and cellular tolerance represents decreased sensitivity to a given drug concentration. It is an example of biochemical regulation at the cellular level to maintain homeostasis. Physical dependence is both a physiologic and a biochemical adaptation to an addicting drug that allows the addicted individual to appear seemingly normal while under a drug concentration that produces the desired effect. By definition, physical dependence is accompanied by some degree of tolerance. The 'withdrawal syndrome' is often characterized biologically by effects that are opposite to the acute pharmacological actions of the drug itself. Removal of the drug will unmask an underlying pathophysiology that is noted by odd behaviour. Re-establishing an effective drug concentration relieves these abnormalities. .Pojam zavisnosti se pominje u razliÄitim kontekstima i nije ograniÄen samo na zloupotrebu lekova veÄ i na aktivnosti koje karakteriÅ”e gubitak samokontrole i kontinuirano uzimanje raznih sredstava zavisnosti. Neki istraživaÄi razlikuju dve vrste zavisnosti: jednu, koja nastaje koriÅ”Äenjem sredstava zavisnosti (alkohol, lekovi, puÅ”enje) i drugu, koju karakteriÅ”e riziÄno ponaÅ”anje (kockanje, zavisnost od hrane, Å”oping, seksualna zavisnost). Poznato je da su mnogi zavisnici uživaoci viÅ”e sredstava zavisnosti istovremeno. Sredstva koja izazivaju zavisnost koriste osobe u stanju stresa, u želji da takvo stanje lakÅ”e prevaziÄu. Tako Äe osobe koje probleme reÅ”avaju konfrontacijom posegnuti za stimulansima dok Äe se osobe sklone 'povlaÄenju' okrenuti ka depresorima. Ljudi koji stres prevazilaze imaginacijom i fantazijom preferiraju halucinogena jedinjenja. Ova veza izmeÄu ponaÅ”anja i odreÄenih lekova je biohemijski determinisana. BioloÅ”ki mehanizam nastanka zavisnosti definisao je Milkman: 'zavisnost jer samoindukovana promena u neurotransmisiji koja rezultira problematiÄnim socijalnim ponaÅ”anjem'. Ova definicija istovremeno obuhvata fizioloÅ”ki, biohemijski i socijalni aspekt procesa nastanka zavisnosti. Neurotransmisija je osnova biohemijske aktivnosti. Male molekule, neurotransmiteri, oslobaÄaju se iz presinaptiÄkog neurona u sinaptiÄku pukotinu. Nakon oslobaÄanja neurotransmiteri bivaju izloženi delovanju enzima ili se vezuju za receptore na postsinaptiÄkoj membrani i aktiviraju enzim adenilat ciklazu. Ovaj enzim konvertuje adenozin trifosfat (ATP) u cikliÄni adenozin monofosfat (cAMP). cAMP poveÄava osetljivost membrane i omoguÄava dalju neurotransmisiju. Prema sposobnosti da menjaju brzinu neurotransmisije sva jedinjenja se mogu podeliti na: stimulanse (lekovi koji poveÄavaju biohemijsku aktivnost: amfetamini, metamfetamini, kokain, nikotin), depresore (alkohol, heroin, morfin, kanabis, barbiturati) i halucinogene (grupa psihoaktivnih jedinjenja koja izaziva vidne i sluÅ”ne halucinacije). Kada se neurotransmisija jednom promeni, CNS nastoji da uspostavi stanje koje je postojalo pre unoÅ”enja sredstva zavisnosti. Uspostavljanjem prvobitne brzine neurotransmisije razvija se tolerancija prema unetom jedinjenju. Postoje dve vrste tolerancije: metaboliÄka i Äelijska. MetaboliÄka tolerancija se manifestuje kao poveÄani metabolizam unetih jedinjenja dok Äelijska nastaje kao posledica smanjene osetljivosti receptora. I jedna i druga vrsta tolerancije predstavljaju primer biohemijske regulacije homeostaze na Äelijskom nivou. FiziÄka zavisnost je fizioloÅ”ko i biohemijsko prilagoÄavanje na sredstva zavisnosti; zavisnik izgleda 'normalno' dok je pod dejstvom unetih supstanci. FiziÄka zavisnost je, po definiciji, praÄena odreÄenim stepenom tolerancije. Prestankom uzimanja sredstava zavisnosti, kod fiziÄki zavisnih osoba, javlja se apstinencijalni sindrom. Apstinencijalni sindrom prate bioloÅ”ki efekti suprotni od farmakoloÅ”kog delovanja samog leka tj. dolazi do demaskiranja patofiziologije koje je praÄeno 'Äudnim' ponaÅ”anjem. Ponovnim uzimanjem efektivne koncentracije sredstva koje izaziva zavisnost prestaju simptomi.
In vitro procena i karakterizacija lekāplazma protein interakcije
The characterization of drug-protein plasma interactions is a routinely performed
part of drug discovery process. The unbound concentration of the drug depends on the
binding affinity to plasma proteins, which consequently affects its therapeutic effect,
absorption, distribution, metabolism and excretion (1). The most important plasma proteins
are human serum albumin (HSA), lipoproteins and alpha-1 acid glycoproteins (AGP). The
liquid chromatography can be successfully used for in vitro estimation of plasma protein
binding affinity using HSA or AGP modified silica gel as a stationary phase (2). The
interaction with HSA has been tested for a wide range of 33 pharmacologically active
compounds including dipeptidyl peptidase IV inhibitors, angiotensin-converting enzyme
inhibitors, Ī²-blockers, calcium channel blockers and serotonin/dopamine receptor ligands
under reversed-phase conditions. The drug-HSA interaction was interpreted by using the
retention modeling, and by selecting the most significant structural characteristics that have
an influence on the retention mechanism. The small structural differences, which are
reflected in different lipophilicity and polarity, affect the drug-HSA interaction. The retention
of the compounds was successfully defined by using the quadratic equation. The isocratic
(logk(14%)) and extrapolated factors (b0(LSS)) showed a high correlation with the
experimentally available data, and in silico estimated affinity for HSA. The structural
properties and charged parts of the molecule surface have been found to significantly affect
the HSA mechanism. The obtained results can be successfully applied in further optimization
of the structural characteristics of the newly synthesized compounds in order to achieve the
desired therapeutic and pharmacokinetic effect.Karakterizacija interakcije novosintetisanih jedinjenja sa plazma proteinima je
rutinski deo procesa proizvodnje i otkiÄa novih lekova. Slobodna koncentracije lekovite
supstance zavisi od stepena vezivanja za proteine plazme, Å”to poslediÄno utiÄe na njen
terapijski efekat, apsorpciju, distribuciju, metabolizam i izluÄivanje (1). NajznaÄajniji plazma
proteini su humani serumski albumin (HSA), lipoproteini i alfa-1 kiseli glikoproteini (AGP).
TeÄna hromatografija se uspeÅ”no koristi za in vitro procenu afiniteta vezivanja lekovite
supstance za plazma proteine primenom modifikovane silika gel stacionarne faze sa HSA-om
ili AGP-om, i koriÅ”Äenjem mobilne faze Äiji sastav simulira fizioloÅ”ke uslove (2). Za Å”irok
spektar 33 farmakoloÅ”ki aktivnih jedinjenja koja ukljuÄuju inhibitore dipeptidil peptidaze IV,
inhibitore angiotenzin konvertujuÄeg enzima, Ī²-blokatore, blokatore kalcijumovih kanala i
ligande serotoninskih/dopaminskih receptora ispitana je interakcija sa HSA-om u uslovima
reverzno-fazne teÄne hromatografije. Lek-plazma protein interakcija je definisana na osnovu
mehanizma zadržavanja na HSA stacionarnoj fazi, primenom metode retencionog
modelovanja, kao i izdavajanjem najznaÄajnijih strukturnih karakteristika koje utiÄu na
retenciono ponaÅ”anje. UtvrÄeno je da male strukturne razlike, koje se ogledaju u razliÄitoj
lipofilnosti i polarnosti, utiÄu na interakciju sa HSA-om. Kvadratnim modelom je uspeÅ”no
definisano retenciono ponaŔanje ispitivanih jedinjenja. Izokratski (logk(14%)) i
ekstrapolisani retencioni faktor (b0(LSS)) su pokazali visok stepen slaganja sa
eksperimentalno dostupnim i in silico procenjenim afinitetom za HSA. Ustanovljeno je da
strukturna svojstva (broj dvostrukih veza, aromatiÄni prstenovi, benzil, arlil supstituenti) i
naleketrisani fragmenti povrÅ”ine molekula znaÄajno utiÄu na HSA interakciju. Dobijeni
rezultati se mogu uspeŔno primeniti u daljoj optimizaciji strukturnih karakteristika
novosintetisanih jedinjenja i postizanja željenih terapijskih i farmakokinetiÄkih ciljeva.VIII Kongres farmaceuta Srbije sa meÄunarodnim uÄeÅ”Äem, 12-15.10.2022. Beogra
The fauna of hoverflies (Diptera: Syrphidae) of Vojvodina province, Serbia
Many hoverfly species of faunal and zoogeographical interest are found in Serbia's northern province of Vojvodina due to the diversity of its biotopes. In this paper, the presence of 252 species of hoverflies (Diptera: Syrphidae) from 69 genera is documented. Five species are here recorded for the first time in Serbia: Anasimyia contracta Claussen & Torp Pedersen, 1980; Anasimyia transfuga (Linnaeus, 1758); Eristalinus megacephalus (Rossi, 1794); Helophilus hybridus Loew, 1846; and Mallota fuciformis (Fabricius, 1794). One species is recorded for the first time in Vojvodina: Cheilosia brunnipennis (Becker, 1894). The records of 12 species from Vojvodina Province are the only ones on the Balkan Peninsula, while the records of 15 species are the only ones in Serbia
Fenotipska varijabilnost reproduktivnih osobina sanske rase koza
Phenotype variability of the basic reproductive parameters research was conducted on Sanska goat population. This research has determined gestation length of 150,52 days and goat fertility of 173,13%. Singles body weight at birth was 3,53 kg, and twins 2,75 kg. Reproductive parameters phenotype variability results that were determined in this research are in accordance with literature.Istraživanje fenotipske varijabilnosti osnovnih reproduktivnih osobina obavljeno je na populaciji koza sanske rase. Istraživanjem je obuhvaÄeno 67 mladih koza koje se prvi put jare. Analizirana su sledeÄa svojstva: dužina bremenitosti, broj jaradi u leglu - plodnost koza i telesna masa jaradi na roÄenju. Ovim istraživanjima je utvrÄena dužina gestacionog perioda od 150,95 dana i plodnost koza od 173,13%. Telesna masa jaradi jedinaca na roÄenju bila je 3,53 kg a blizanaca 2,75 kg. Dobijeni rezultati o fenotipskoj varijabilnosti reproduktivnih osobina koza sanske rase u saglasnosti su sa literaturom
Trendovi u dizajniranju antidepresiva i anksiolitika
Depression constitutes an international health problem. It is estimated that 320 million people worldwide are clinically depressed. Effective antidepressant treatments have been available for more than 40 years. Although modern antidepressants lack many of the side-effects and toxicity of the first generation tricyclics and monoamine oxidase inhibitors, their efficiency has not been substantially improved comparing to older agents. Unfortunately, the modern drug discovery technologies of combinatorial chemistry and throughput screening are based on relatively simple in vitro assays and lack pre-clinical model of depression make this research difficult. Most antidepressants require additional time to achieve therapeutic effects and there is a certain population of patients resistant to current therapies which means that etiology of depression is too complex. Coming research should clarify true depression mechanism and identify new targets of the third antidepressants generation. Anxiety is a normal emotion and essential part of response to stressful and threatening stimuli. At present, a numerous drugs with various mechanism of action are available for pharmacoterapy of anxiety disorders. The benzodiazepines represent the most important drugs in the treatment of anxiety. In addition to their anxiolytic properties, benzodiazepines possess sedative, hypnotic, anticonvulsant and other effects but side effects also-upon prolonged administration they produce withdrawal symptoms and dependency. Research has shown that cholecystokinin and corticotrophin-releasing factor are important neurotransmiters and may have role in the mediation of anxiety. Neuropeptide Y has shown an anxiolytic effect in several animal models. CCK, CRF and neuropeptid Y receptor agonists and antagonists are targets of new anxiolitic drugs.Anksioznost je normalna emocionalna reakcija na preteÄi ili stresni stimulans. U farmakoterapiji ove bolesti koristi se veliki broj lekova razliÄitog mehanizma delovanja od kojih su benzodiazepini najvažniji. Benzodiazepini, pored anksiolitiÄkog poseduju sedativni, hipnotiÄki, antikonvulzivni i druge efekte ali posle duže upotrebe razvija se tolerancija, dovode do zavisnosti i Äesto su predmet zloupotrebe. Novija istraživanja su pokazala da, pored serotonina i noradrenalina i drugi neurotransmiteri kao Å”to su holecistokinin (CCK) i oslobaÄajuÄi faktor za kortikotropin (CRF) imaju znaÄajnu ulogu u anksioznosti. Neuropeptid Y (NPY) takoÄe pokazuje anksiolitiÄki efekat na životinjama. Agonisti i antagonisti receptora holecistokinina, oslobaÄajuÄeg faktora za kortikotropin i neuropeptida Y su cilj sinteze novih anksiolitika
Preliminary identification on key indicators for air quality risk assessment from landfill
Landfilling is still the most widely used form of waste disposal although it is associated with a number of environmental issues primarily related to unregulated and partially controlled landfills that are numerous in Serbia. Landfill gas, mostly composed of methane, represents a high risk for human health and environment. This paper gives preliminary identification of criteria for quantification of methane risk impact on air in the immediate vicinity of landfills in Serbia. Four types of criteria were defined. Those criteria consist of sub-criteria that must be considered when considering the potential risks to the environment and human health
Molecular Docking Analysis of Novel Thiourea Derivatives of Naproxen with Potential Antitumor Activity
Naproxen, as a propionic acid derivative, causes serious gastrointestinal side effects due to the presence of free carboxylic group. In that sense, masking of carboxylic group with other pharmacophores may be a promising strategy to decrease gastrointestinal toxicity. Thiourea derivatives have been intensively investigated as potential antitumor drugs, whereby their activity is based on potential inhibition of protein kinases, topoisomerases, carbonic anhydrase and sirtuins. In addition, it was shown that inhibition of certain protein kinases might reverse resistance to chemotherapeutic drugs by enhancing the cell death in the presence of low concentrations of drug. Twenty new thiourea derivatives of naproxen were designed and their binding to four selected protein kinases involved in tumor multidrug resistance (AKT2, mTOR, EGFR and VEGFR1) was estimated using two molecular docking programs (AutoDock Vina and OEDocking). According to OEDocking, the highest potential to inhibit AKT2 and mTor has derivative 1, while derivative 20 demonstrates the highest potential towards EGFR and VEGFR1. According to AutoDock Vina, the highest potential for inhibition of EGFR, AKT2 and VEGFR1 have derivatives 16 and 17. Therefore, derivatives 1, 16, 17 and 20 are potentially the most potent protein kinase inhibitors that could be further synthesized and tested for anticancer activity
HOVERFLY FAUNA (DIPTERA: SYRPHIDAE) OF THE LANDSCAPE OF OUTSTANDING FEATURES āVLASINAā
In the many years of research organized between 1977 and 2017, a total of 76 hoverfly species were collected in the protected Landscape of Outstanding Features āVlasinaā (southeastern Serbia) on six localities. Among the identified taxa there is a rare species, Cheilosia longula (Zetterstedt, 1838), which is protected in Serbia. Additionally, one potentially new hoverfly species is registered (Merodon aff. cinereus). The first species checklist of hoverflies for Vlasina is proposed
Uticaj uzrasta i razliÄite doze prirodnog gonadotropnog hormona na reproduktivne pokazatelje ovaca u sezoni anestrije
In this paper results of age and different dosages of PMSG (500 and 750 i.u) on young II dāfrans sheep fertility trait in anestric season are discussed. This research has clearly shown that first conception of young II dāfrans sheep can be done at the age of 12-14 months as they reacted better at hormone dosages, compared to the group of sheep that was 11-13 months old. Higher dose of PMSG of 750i.u(for testing group) compared to 500i.u (control group) led to the result that test group had higher fertility rate by 30.66% compared to control group. Higher fertility of test group is represented by higher number of twins by 24.13% and triplets by 5.18% compared to control group.U radu se analizira uticaj uzrasta ovaca (dviski) i razliÄite doze (500:750 i.j.) prirodnog gonadotropina PMSG-a na reproduktivne pokazatelje ovaca II d frans rase u periodu anestrije. Ova istraživanja su jasno pokazala da prva koncepcija dviski treba da se obavi u uzrastu grla 12-14 meseci. VeÄa doza PMSG-a od 750 i.j. (kod ogledne grupe) u odnosu na 500 i.j. (kod kontrolne grupe) dovela je do toga da je ogledna grupa imala veÄu plodnost za 30,66% u odnosu na kontrolnu grupu. VeÄa plodnost ogledne grupe je posledica raÄanja veÄeg broja blizanaca za 24,13% i trojki za 5,18% kod ogledne u odnosu na kontrolnu grupu
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