Biophysics is an evolving, multidisciplinary subject which applies physics to biological systems and promotes an understanding of their physical properties and behaviour. Biophysics: An Introduction, ...is a concise balanced introduction to this subject. Written in an accessible and readable style, the book takes a fresh, modern approach with the author successfully combining key concepts and theory with relevant applications and examples drawn from the field as a whole. Beginning with a brief introduction to the origins of biophysics, the book takes the reader through successive levels of complexity, from atoms to molecules, structures, systems and ultimately to the behaviour of organisms. The book also includes extensive coverage of biopolymers, biomembranes, biological energy, and nervous systems. The text not only explores basic ideas, but also discusses recent developments, such as protein folding, DNA/RNA conformations, molecular motors, optical tweezers and the biological origins of consciousness and intelligence. Biophysics: An Introduction* Is a carefully structured introduction to biological and medical physics * Provides exercises at the end of each chapter to encourage student understanding Assuming little biological or medical knowledge, this book is invaluable to undergraduate students in physics, biophysics and medical physics. The book is also useful for graduate students and researchers looking for a broad introduction to the subject.
Prethodna istraživanja pokazala su da BPC 157 sprječava nastanak okluzivnog tromba i ubrzava razgradnju već stvorenog ugruška nakon formiranja anastomoze aorte, a da, s druge strane, smanjuje vrijeme ...krvarenja kod štakora tretiranih varfarinom, heparinom i aspirinom. Temeljem toga, nametnula se potreba određivanja njegova utjecaja na agregaciju trombocita i viskoelastična svojstva krvnog ugruška. Za ispitivanje eventualne uključenosti NO sustava u djelovanje BPC 157 korišten je selektivni inhibitor topljive gvanilil ciklaze, ODQ. Životinje (n=60) su najprije podijeljene u skupine ovisno o tome koji antiagregacijski lijek primaju (1.aspirin, 2.klopidogrel, 3.cilostazol), a te skupine su tada nasumično podijeljene u četiri podskupine koje su primale a) fiziološku otopinu, b) BPC 157, c) ODQ, d) BPC 157 + ODQ. Mjerenja su izvršena impendancijskom agregometrijom s 4 različita agonista (ADP, AA, AA/PGE1, kolagen), te rotacijskom tromboelastometrijom s 3 različita agonista (preko vanjskog i unutarnjeg puta zgrušavanja, te bez doprinosa trombocita). Iz rezultata dobivenih usporedbom podskupina a i b, te b i d unutar svake skupine možemo zaključiti da BPC 157 oporavlja inhibiranu agregaciju trombocita, ali da nema utjecaja na viskoelastična svojstva krvnog ugruška u ispitivanih štakora.
As a natural extension of previous research that confirmed the role of BPC 157 in the prevention of obstructive thrombus formation and rapid destruction of an already formed one after aortic anastomosis, but also shortening of the bleeding time in rats treated with anticoagulants and aspirin, there was a necessity to determine how BPC 157 influences platelet aggregation and viscoelastic properties of the blood clot. To assess its relation to NO system, sCG selective inhibitor (ODQ) was used. Rats (n=60) were divided into groups depending on the antiaggregatory drug they were treated with (1.aspirin, 2.clopidogrel, 3.cilostazol). Groups were further divided into four subgroups treated with a) normal saline, b) BPC 157, c) ODQ, d) BPC 157 + ODQ. Impendance aggregomery measurements with four agonists (ADP, AA, AA/PGE1 and collagen), and also rotational thromboelastometric measurements with 3 agonists (for initiating external and internal coagulation pathway and without platelet contribution) were performed. Based on the results obtained by comparing subgroups a versus b, and b versus d in each group, we can conclude that BPC 157 rescues inhibited platelet aggregation, but it has no effect on viscoelastic properties of the blood clot.
Cilj ovog istraživanja je prikazati učinke i razlike u toksičnosti te prooksidativne i antihemostatske mehanizme triju biljnih formulacija namijenjenih ljudskoj uporabi kao dodaci prehrani, a koja ...sadrže pripravak biljke Ginkgo biloba, dostupne na području Republike Hrvatske. Istražen je i njihov učinak u kombinaciji s antihemostatskim lijekovima, acetilsalicilnom kiselinom i varfarinom. Istraživanje je provedeno na životinjskom modelu štakora. Testovima agregacije i koagulacije dokazano je da svi korišteni biljni pripravci produžuju vrijeme agregacije trombocita dok na koagulaciju nemaju statistički značajan učinak. Dokazano je da korištenje biljnih pripravaka u kombinaciji s lijekovima mijenja vrijednosti mjerenih biljega oksidativnog stresa, aktivnost enzima superoksid dismutaze (SOD) i katalaze te koncentraciju reduciranog glutationa (GSH) i malondialdehida (MDA) u tkivu jetre, bubrega, slezene i mozga, te u krvi. Dobiveni rezultati ukazuju na potrebu veće pozornosti prilikom upotrebe pripravka ginka i različitih antihemostatskih lijekova u svakodnevnoj kliničkoj praksi.
The aim of this study was to demonstrate the effects and the differences in toxicity and prooxidant and antihemostatic mechanisms of three herbal dietary supplements, containing extract of Ginkgo biloba, that are available in Croatia. The goal was also to investigate their efect in combination with antihemostatic drugs, acetylsalicylic acid and warfarin. The study was conducted on animal model. Platelet aggregation and coagulation tests proved that all used herbal products prolong platelet aggregation, while on coagulation they had no statistically significant effect. It has been shown that the use of herbal dietary supplements in combination with medicaments changes the value of the measured biomarkers of oxidative stress, the activity of superoxide dismutase (SOD) and catalase and concentration of glutathione (GSH) and malondialdehyde (MDA) in tissues of liver, kidney, spleen and brain, and also in blood. The results suggested that the greater attention should be paid to the usage of these products in clinical practice.
Serotoninski prijenosnik (5HT prijenosnik, 5HTT) predstavlja ciljnu molekulu djelovanja antidepresivnih lijekova iz skupine selektivnih inhibitora povratnog unosa serotonina (SSRI). Iako često ...korišteni, ovi lijekovi ostvaruju terapijski učinak samo kod manjeg broja (do 50 %) bolesnika, a razlozi za to nisu poznati. Nalaz povezanosti terapijskog odgovora s polimorfizmom gena za 5HTT uputio je na moguću ulogu konstitucijske serotoninske homeostaze u kliničkom odgovoru na SSRI. Primjenom originalnog životinjskog modela, Wistar-Zagreb 5HT štakor, čije sublinije imaju konstitucijski pojačanu (5HT-visoki) ili smanjenu (5HT-niski) aktivnost trombocitnog 5HTT, u ovom radu je istražen odnos između konstitucijske 5HT homeostaze i odgovora na tretman SSRI-om. Farmakološka aktivacija 5HT sustava izazvana je jednokratnom ili kroničnom primjenom SSRI-a fluoksetina, a cilj je bio usporediti sublinije s obzirom na učinke fluoksetina na (i) aktivnost 5HTT i razinu 5HT u mozgu i na periferiji, (ii) razinu mRNA za 5HTT i receptor 5HT1A u mozgu te (iii) odabrana ponašanja modulirana serotoninom. Jednokratni tretman fluoksetinom doveo je do inhibicije aktivnosti trombocitnog 5HTT, koja je bila jače izražena kod životinja iz 5HT-visoke sublinije, te do porasta razine plazmatskog 5HT, koji je bio veći kod životinja iz 5HT-niske sublinije. Kronična primjena lijeka dovela je do značajnog pada razine trombocitnog serotonina, koji je bio veći kod životinja iz 5HT-niske sublinije, te do pada plazmatskog serotonina, koji je bio veći kod životinja iz 5HT-visoke sublinije. Smanjenje ponašanja nalik na anksioznost, kao i porast istraživačke i lokomotorne aktivnosti nakon kroničnog tretmana fluoksetinom bilo je prisutno samo kod životinja iz 5HT-visoke sublinije, a praćeno je promjenama u mozgu koje su bile vidljive kao tendencija povećanja ekspresije gena za 5HT1A receptor u hipokampusu te ekspresije gena za 5HTT u regiji jezgara rafe. S druge strane, kod životinja iz 5HT-niske sublinije, kronična primjena fluoksetina dovela je do pada kortikalne ekspresije mRNA za 5HTT i receptor 5HT1A, te tendencije pada razine 5HT u moždanoj kori, dok učinci na ponašanje nisu bili značajni. Rezultati istraživanja pokazuju da je konstitucijska serotoninska homeostaza važan čimbenik odgovora na tretman fluoksetinom. Sublinije Wistar-Zagreb 5HT štakora mogu biti koristan model u istraživanju neurobiološke osnove različitog odgovora pojedinaca na terapiju antidepresivima, kao i za vrednovanje trombocita kao perifernog modela za predviđanje terapijskog odgovora.
Serotonin transporter (5HT transporter, 5HTT) represents the target molecule of selective serotonin reuptake inhibitors (SSRIs) acting as antidepressant drugs. Although commonly used, these drugs produce a therapeutic effect only in a small number of patients (up to 50 %), and the reasons for that are not known. The association between therapeutic response and 5HTT gene polymorphism has pointed out to possible role of the constitutional serotonin homeostasis in clinical response to SSRI. Using the original animal model, Wistar-Zagreb 5HT rats, whose sublines have constitutional high (high-5HT) or low (low-5HT) of platelet 5HTT activity, we have investigated the relationship between constitutional 5HT homeostasis and responses to SSRI treatment. Following pharmacological activation of 5HT system, induced by single or repeated doses of SSRI fluoxetine, we have compared these sublines with respect to (i) the 5HTT activity and the 5HT levels in the brain and blood, (ii) the expression of 5HTT and 5HT1A receptor genes in the brain, and (iii) the selected behaviors modulated by serotonin. Acute treatment with fluoxetine led to inhibition of platelet 5HTT activity, which was more pronounced in animals from the high-5HT subline, and to increase of plasma 5HT level, which was higher in animals from the low-5HT subline. Chronic administration of the drug caused a significant decrease of platelet serotonin levels, which was higher in animals from the low-5HT subline, and a decrease of plasma 5HT levels, which was higher in animals from the high-5HT subline. The reduction of anxiety-like behavior, along with the increase of exploratory and locomotor activity after chronic treatment with fluoxetine was observed only in animals from the high-5HT subline, and was accompanied by the tendency towards increase of 5HT1A receptor gene expression in hippocampus and the tendency towards increased expression of 5HTT gene in raphe nuclei. On the other hand, in animals from the low-5HT subline, chronic application of fluoxetine led to decrease in 5HTT and 5HT1A receptor mRNA levels and tendency towards decrease in 5HT in the cerebral cortex. The obtained results show that constitutional serotonin homeostasis is an important factor in response to fluoxetine treatment. Furthermore, Wistar-Zagreb 5HT sublines may represent a useful model in studding the neurobiological basis of a different individual response to antidepressants, as well as in evaluating platelets as a peripheral model for predicting the therapeutic response.
Biološka aktivnost roda Centaurea pripisuje se spojevima iz skupine terpena i flavonoida čija su antioksidacijska, antibakterijska, citotoksična i slična ljekovita svojstva dokazana. Cilj rada je ...odrediti sadržaj i sastav fitokemikalija ekstrakata hrvatske endemične biljne vrste Centaurea ragusina L. sakupljene na prirodnom lokalitetu, uzgojene u uvjetima in vitro i aklimatizirane na vanjske uvjete kao i njihovu antioksidacijsku, antibakterijsku i citotoksičnu aktivnost. U svrhu razjašnjenja biološke aktivnosti proučavane su interakcije ekstrakata, frakcija i spojeva s polinukleotidima. U etanolno vodenim ekstraktma izmjeren je najviši sadržaj fenola, flavonoida i hidroksicimetnih kiselina. Etanolno vodeni i etanolno etanolni ekstrakti pokazuju značajnu antioksidacijsku aktivnost neovisno o podrijetlu biljaka. Ekstrakti listova priređeni u etanolu, većina ispitivanih frakcija kao i dva izolirana seskviterpenska laktona pokazali su značajnu antibakterijsku aktivnost na Staphylococcus aureus ATCC 25923. Svi vodeni vodeni ekstrakti pokazuju značajni stabilizacijski učinak na DNA i RNA. Gotovo svi testirani ekstrakti te frakcije CRE01_06-10 pokazuju značajnu citotoksičnu aktivnost na testiranim tumorskim staničnim linijama.
Biological activity of Centaurea genus is mainly attributed to compounds of the terpenoid and flavonoid type which showed antioxidant, antimicrobial, cytotoxic and other therapeutic properties. The goal of this work was to determine polyphenol content and composition of phytochemicals in Croatian endemic plant species Centaurea ragusina L. collected at natural habitats, cultivated in vitro and acclimated plants as well as to estimate their antioxidant, antibacterial and cytotoxic activity. Ethanolic/aqueous extracts showed the highest level of total phenols, flavonoids and hydroxycinnamic acid. Ethanolic/aqueous and ethanolic/ethanolic extracts showed significant antioxidant activity regardless of the plant origin. Crude ethanolic/ethanolic extract of leaves, almost all tested fractions and two isolated sesquiterpene lactones showed significant antibacterial activity against Staphylococcus aureus ATCC 25923. All aqueous/aqueous extracts showed significant stabilisation effects of DNA and RNA. Almost all tested extracts and fractions CRE01_06-10 exhibited significant inhibitory activities against all tested cancer cell lines.
Prekomjerno stvaranje reaktivnih kisikovih spojeva (ROS) u stanicama uzrokuje ireverzibilne modifikacije proteina, kao što je na primjer karbonilacija, koje utječu na njihovu strukturu i funkciju te ...na stabilnost proteoma. Istraživanja provedena na bakterijama i beskralješnjacima su pokazala postojanje korelacije između oštećenja proteoma i stanične smrti. Cilj ovog rada bio je utvrditi postoji li takva poveznica između stanične smrti i oštećenja proteina imortalnih staničnih linija dobivenih iz primarnog tumora (SW480) i metastaze (SW620) adenokarcinoma debelog crijeva. Izlaganjem staničnih linija oksidativnom stresu utvrdili smo da stanična linija SW620 ima nižu razinu oštećenih proteina od stanica SW480 te je otpornija na oštećenja proteoma izazvanih UVC zračenjem. Razlog povećane otpornosti proteoma stanica SW620 mogla bi biti niska razina ROS-a u odnosu na stanice SW480 i veća stabilnost proteoma. Usporednom analizom proteoma staničnih linija SW480 i SW620 u trenutku kada je smrtnost u populaciji iznosila 90% utvrdili smo da su mogući razlozi povećane osjetljivosti stanica SW480 narušene funkcije sustava za održavanje proteostaze i odstranjivanja oštećenih proteina te smo identificirali proteine koji bi mogli biti potencijalne mete u razvoju protutumorskih terapija.
The excessive production of reactive oxygen species (ROS) in cells induces irreversible protein modifications, carbonylation, that impairs protein structure and function, as well as proteome stability. The correlation between proteome damage and cell death is well established in bacteria and invertebrates and the aim of this research was to investigate the relationship between mortality and protein damage of immortal cell lines derived from primary tumor adenocarcinoma SW480 and its metastasis SW620. We found that SW620 cell line is more resistant to UVC-induced oxidative damage relative to SW480 cells. The reason for greater resistance of SW620 cells could be lower ROS level compared to SW480 and greater proteome stability. The differential analysis of proteomes of two cell lines after 90% UVC-induced mortality shows that SW480 displays greater sensitivity due to the damage of proteome quality system and the ability to remove oxidative damaged proteins. Also, we identified proteins that could be possible targets in anti-cancer therapy.
