Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 16

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  cholesterol
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Effects of Exercise and/or Diet Programs on Kinanthropometric and Metabolic Parameters in Obese Children: a Pilot Study

100%
Saavedra J., Garcia-Hermoso A., Escalante Y.
Journal of Human Kinetics
|
2011
|
vol. 29
67-78
EN
This study was aimed at determining the effects of implementing a medium-term (six-month) exercise and/or a diet program on the kinanthropometric and metabolic parameters of obese children. The participants were 42 subjects (27 boys, 15 girls), whose ages were between 8 and 11, divided into three groups according to the program they followed. The E group followed a physical exercise program (three 90-minute sessions per week), the D group a low calorie diet, and the E+D group both interventions. A repeated-measure ANOVA was used to compare measurements of the participants' kinanthropometric and metabolic parameters at different times of the program, with the means being compared using the Tukey post-hoc test. It was found that medium-term intervention based on the combination of exercise and low calorie diet improved the obese children's kinanthropometric and metabolic parameters, especially those related to the lipid profile. Also, this combined program was more effective in controlling weight than the exercise or low calorie diet interventions alone.
2
Content available remote

A simple method for the determination of the cholesterol esterase activity

100%
Stępień A., Gonchar M.
Acta Biochimica Polonica
|
2013
|
vol. 60
|
issue 3
401-403
EN
The proposed method determines the activity of cholesterol esterase (CEH) and takes advantage of its ability to catalyze the hydrolysis of cholesterol esters naturally present in human serum. The assay is based on Allain's method of spectrophotometric determination of cholesterol by means of cholesterol oxidase, peroxidase, but using 3,5-dichloro-dihydroxybenzenesulfonic acid (DHBS) as phenolic chromogen and human serum as a source of substrate for the CEH as a novelty. Furthermore, it is characterized by low costs and high precision. It can be employed to control the activity of CE preparations used for the preparation of enzymatic kits for the determination of cholesterol or for screening of potential bacterial enzyme producers.
3
Content available remote

A Lennard-Jones-like perspective on first order transitions in biological helices

100%
Oskolkov N., Bohr J.
Open Physics
|
2013
|
vol. 11
|
issue 3
357-362
EN
Helical structures with Lennard-Jones self-interactions are studied for optimal conformations. For this purpose, their self-energy is analyzed for extrema with respect to the geometric parameters of the helices. It is found that Lennard-Jones helices exhibit a first order phase transition from a state with large curvature of the helical backbone to one with a small curvature. I.e. from a dense helix to an extended helix. A transition from one helical structure to another is a phenomenon known to take place in self-assembling helices formed in multicomponent solutions with cholesterol.
4
Publication available in full text mode
Content available

Obesity, lipid profiles and oxidative stress in children after liver transplantation

100%
Czubkowski P., Wierzbicka A., Pawłowska J., Jankowska I., Socha P.
Acta Biochimica Polonica
|
2017
|
vol. 64
|
issue 4
661-665
EN
Purpose. In adult liver transplant recipients, coronary artery disease and congestive heart failure are significant cause of morbidity and mortality. This may be attributed to the long-term immunosuppressive treatment, mostly with calcineurin inhibitors and steroids, which in long-term may be associated with hyperlipidemia, oxidative stress and cardiovascular complications. Since such data for children is sparse, the aim of this study was to assess the lipid and oxidative stress markers after pediatric liver transplantation (LTx). Method. We performed prospective analysis of 74 children, at the median age of 7.9 (2.8-11.6) years, 3.2 (1.2-4.3) years after LTx. We assessed the BMI Z-scores, cholesterol fractions (LDLc, HDLc, VLDLc), triglicerides, apolipoproteins (ApoAI, ApoB, ApoE), LCAT, insulin resistance by HOMA-IR and markers of oxidative stress and atherosclerosis: glutathione (GSH), glutathione peroxidase (GPx), asymmetrical dimethyl arginine (ADMA) and oxidized low-density lipoprotein (oxyLDL). At baseline, the results were compared with a healthy age-and-sex matched control group. After 3.1±0.3 year follow-up we repeated all investigations and compared them with the baseline results. RESULTS. At the baseline, we investigated 74 patients 3.2 (1.2-4.3) years after LTx, at the median age of 7.9 (2.8-11.6) years. The prevalence of overweight or obesity (BMI >85th percentile) was 23% and was more common in girls (24% vs 20%). Fourteen patients had TCH >200 mg%, 9 patients had LDLc >130 mg% and TG were at normal levels in all patients. Compared to the controls, there were no significant differences in lipid profiles but we found decreased GSH (p<0.001) and GPx (p<0.001) which play role as an antioxidant defense. OS markers were higher in the study group: ADMA (p<0.001), and oxyLDL (p<0.0001). Insulin resistance by HOMA-IR was increased in the study group (p=0.0002) but fasting glucose remained within normal ranges in all patients. After 3.1-year follow-up, the BMI >95th and >85Th percentile was present in 8% and 14% respectively. ADMA and oxyLDL decreased, whilst GSH and GPx increased when compared to the baseline. There was also significant decrease in apoB and Lp(a). Conclusion. Children after LTx had normal lipid profiles when compared to controls, however there is a tendency for hypercholesterolemia and obesity, which may play a role in cardiovascular complications in the future. Some markers of oxidative stress were increased after LTx, however further investigations are required to establish its clinical significance.
5
Publication available in full text mode
Content available

Domeny błonowe komórek eukariotycznych i prokariotycznych i ich udział w przekazywaniu sygnału

89%
Prymas K., Kwiatkowska K.
Kosmos
|
2017
|
vol. 66
|
issue 4
691-702
PL
Błona komórkowa komórek eukariotycznych jest niejednorodna i charakteryzuje się obecnością domen nazywanych tratwami błonowymi. Są to liczące kilka nanometrów dynamiczne skupiska sfingolipidów, cholesterolu i wybranych białek, zwłaszcza palmitoilowanych, które wyodrębniają się z otaczającego je środowiska glicerofosfolipidów. Labilne nanodomeny zlewają się w większe struktury, platformy sygnałowe, stabilizowane przez interakcję z cytoszkieletem podbłonowym w czasie aktywacji szeregu receptorów zaangażowanych w reakcje wrodzonej i nabytej odporności. Paradoksalnie, niektóre wirusy i bakterie wykorzystują tratwy błonowe jako miejsca inwazji/opuszczania komórek gospodarza. Z drugiej strony, w błonie bakterii wykryto rejony, w których także skupiają się wybrane białka sensorowe i enzymy, co sugeruje udział domen błony bakteryjnej w procesach przekazywania sygnału. Skład lipidowy bakteryjnych domen błonowych jest słabo poznany, a rolę w ich formowaniu przypisuje się białku flotylinie. Heterogenna organizacja błony komórkowej jest zatem zachowanym ewolucyjnie sposobem zapewnienia właściwej przestrzennej organizacji receptorów oraz białek i lipidów biorących udział w ich kaskadach sygnałowych, która stała się szczególnie istotna dla funkcjonowania komórek układu odpornościowego człowieka i zwierząt.
EN
The plasma membrane of eukaryotic cells contains domains named rafts which are nonscale dynamic assemblies of sphingolipids, cholesterol and selected proteins, mainly palmitoylated ones. During stimulation of distinct immune receptors labile rafts merge into larger structures which are stabilized by submembraneous cytoskeleton and serve as signaling platforms of those receptors. Paradoxically, rafts are also utilized by some viruses and bacteria to invade/escape host cells. On the other hand, bacterial plasma membrane contains domains accommodating sensory proteins and several other enzymes which suggests that those domains are sites of signal transduction. Lipid composition of bacterial membrane domains is poorly characterized and a role in their formation is ascribed to proteins named flotillins. Thus, domain organization of the plasma membrane seems to be common to eukaryotic and prokaryotic cells. It facilitates spatial organization of plasma membrane receptors as well as lipids and proteins involved in their signaling pathways. During evolution rafts of the plasma membrane have become important especially for functioning of human and animal immune cells.
6
Publication available in full text mode
Content available

Zawartość cholesterolu we fragmentach tętnic – studium 34 przypadków

88%
Kuzan A., Chwiłkowska A., Kobielarz M.
Annales Academiae Medicae Silesiensis
|
2014
|
vol. 68
|
issue 1
23-27
EN
BACKGROUND Atherosclerosis is a multifactor disease. It is commonly believed that a high cholesterol level in blood plasma is the main factor which is responsible for the formation of atherosclerotic plaques in arteries. Lipid molecules form not only pathological arteries, but are also part of each blood vessel as an important element of cell mem-branes. The aim of this study is to investigate whether the amount of cholesterol in the arteries is correlated with the degree of atherosclerosis. MATERIAL AND METHODS The research material consists of 34 fragments of arteries originated from the bodies of people who died a sudden death. The samples were divided into four groups according to the severity of atherosclerosis. Cholesterol was determined using a colorimetric method with ferric chloride in concentrated phosphoric and sulfuric acid. RESULTS It was observed that the content of arterial cholesterol in the samples increased with the severity of atherosclerosis. The arteries from persons with severe and very high intensification of the disease were characterized by high levels of cholesterol. CONCLUSIONS There is a relationship between the content of cholesterol in the blood vessel wall and the severity of atherosclerosis, but it is not a directly proportional rectilinear relationship due to the fact that plaques with the progression of the disease are not only enriched in lipids but also in cellular and protein components, such as monocytes, macrophages, thrombocytes, necrotic cells, extracellular matrix proteins and others. Further studies are needed to better understand the pathogenesis of atherosclerosis and verify the thesis of the key role of cholesterol in the formation of atherosclerotic lesions.
PL
WSTĘP Miażdżyca jest chorobą wieloczynnikową. Powszechnie uważa się, że głównym czynnikiem odpowiedzialnym za powstawanie blaszek miażdżycowych w tętnicach jest wysoki poziom cholesterolu w osoczu krwi. Cząsteczki tego lipidu wchodzą w skład nie tylko tętnic objętych patologicznym stłuszczeniem, ale też każdego naczynia krwionośnego jako element budulcowy błon komórkowych. Celem pracy jest odpowiedź na pytanie, czy ilość cholesterolu całkowitego w tętnicach jest skorelowana z poziomem zaawansowania miażdżycy. MATERIAŁ I METODY Materiałem badawczym były 34 wycinki tętnic pochodzące ze zwłok ludzi zmarłych śmiercią nagłą. Próbki były podzielone na 4 grupy ze względu na stopień zaawansowania miażdżycy. Cholesterol oznaczano kolorymetryczną metodą z użyciem chlorku żelaza w stężonym kwasie siarkowym i fosforowym. WYNIKI Zaobserwowano, że średnia zawartość cholesterolu w próbkach tętnic wzrastała wraz ze stopniem zaawansowania miażdżycy. Tętnice pochodzące od osób ze znacznym i bardzo dużym nasileniem choroby charakteryzują się wysokim poziomem cholesterolu. WNIOSKI 1. Istnieje związek między zawartością cholesterolu w ścianie naczynia krwionośnego a zaawansowaniem miażdżycy; nie jest to jednak zależność wprost proporcjonalna, gdyż blaszki miażdżycowe wraz z postępem choroby wzbogacane są nie tylko w lipidy, ale także w komórkowe i białkowe składniki, takie jak monocyty, makrofagi, trombocyty, komórki nekrotyczne, białka macierzy zewnątrzkomórkowej i inne. 2. Konieczne są dalsze badania w celu pogłębienia wiedzy na temat patomechanizmu miażdżycy i weryfikacji tezy o nadrzędnej roli cholesterolu w powstawaniu zmian miażdżycowych.
7
Publication available in full text mode
Content available

Rola 7α- hydroksylazy cholesterolu i genu CYP7A1 w fi zjologii i patologii człowieka

75%
Iwanicki T., Balcerzyk A., Żak I.
Annales Academiae Medicae Silesiensis
|
2010
|
vol. 64
|
issue 3-4
48-57
EN
Cholesterol 7α- hydroxylase (CYP7A1) belongs to the big family of cytochrome p450. Biological signifi cance of cholesterol 7α- hydroxylase is associated with beginning of cholesterol transformation to the bile acids. CYP7A1 affi nity to the cholesterol is determined by its unique protein structure, diff erent from the other proteins of cytochrome p450 family. CYP7A1 enzyme is enoded by CYP7A1 gene localized in short arm of chromosome 8. Expression of CYP7A1 gene could be regulated by farnesoid X receptor (FXR) or by kinases, which modulate nuclear receptor`s binding abilities to the gene promoter. Polymorphic variants and mutations present in the promoter region impact on the quality properties of the enzyme. CYP7A1 gene, encoding key enzyme of the cholesterol catabolic pathway is a main candidate to the research of its association with changes of serum lipids levels. Presence of genetic variants can be associated with changed levels of total cholesterol, triglycerides and Low- density lipoproteins (LDL). Promoter polymorphism of CYP7A1 is also main candidate for the research of association with such disease entities as gallbladder stone formation, colon cancer, gallbladder cancer or atherogenic- based diseases.
PL
7α- hydroksylaza cholesterolu (CYP7A1) jest enzymem należącym do dużej rodziny cytochromu p450. Znaczenie biologiczne 7α- hydroksylazy cholesterolu związane jest z rozpoczęciem szeregu przemian cholesterolu do kwasów żółciowych. Powinowactwo CYP7A1 do cholesterolu determinowane jest unikalną budową białka, odmienną od reszty białek rodziny cytochromu p450. Enzym ten kodowany jest przez gen CYP7A1, którego locus znajduje się na ramieniu krótkim chromosomu ósmego. Ekspresja tego genu może być regulowana przy udziale farnezylowego receptora X (FXR), bądź zachodzić poprzez szereg kinaz białkowych, modulujących zdolność przyłączania się swoistych receptorów jądrowych do promotora CYP7A1. Warianty polimorfi czne i mutacje, występujące w regionie promotorowym, wpływają na właściwości jakościowe enzymu. Gen CYP7A1, kodując kluczowy enzym w katabolizmie cholesterolu, jest głównym kandydatem do badań jego związku ze zmianami w osoczowym poziomie lipoprotein. Obecność wariantów genetycznych w promotorze genu CYP7A1 może być związana ze zmienionym poziomem cholesterolu całkowitego, triacylogliceroli czy LDL (Low- Density Lipoprotein). Polimorfizm promotora genu kodującego kluczowy enzym szlaku syntezy kwasów żółciowych i usuwania cholesterolu z organizmu jest głównym kandydatem do badań asocjacyjnych z takimi jednostkami chorobowymi, jak kamica żółciowa, nowotwory jelita grubego i woreczka żółciowego czy choroby o podłożu miażdżycowym.
8
Content available remote

Molecular modelling study of the role of cholesterol in the stimulation of the oxytocin receptor.

75%
Politowska E., Kaźmierkiewicz R., Wiegand V., Fahrenholz F., Ciarkowski J.
Acta Biochimica Polonica
|
2001
|
vol. 48
|
issue 1
83-93
EN
Cholesterol, an integral component of membranes in Eucaryota, is a modifier of membrane properties. In vivo studies have demonstrated that cholesterol can also modulate activities of some G protein-coupled receptors (GPCRs), which are integral membrane proteins. This can result either from an effect of cholesterol on the membrane fluidity or from specific interactions of the membrane cholesterol with the receptor, as recently demonstrated for the cholecystokinin type β (CCKRβ) or the oxytocin receptor (OTR). Using molecular modelling, we studied conformational preferences of cholesterol and several of its analogues. Subsequently, we simulated the distributions of their preferred conformations around the surface of OTR, CCKRβ and a chimeric oxytocin/cholecystokinin receptor. Consequently, we suggest residues on the surface of OTR which are potentially significant in the OTR/cholesterol interaction.
9
Content available remote

Molecular dynamics simulation studies of lipid bilayer systems.

75%
Pasenkiewicz-Gierula M., Murzyn K., Róg T., Czaplewski C.
Acta Biochimica Polonica
|
2000
|
vol. 47
|
issue 3
601-611
EN
The main structural element of biological membranes is a liquid-crystalline lipid bilayer. Other constituents, i.e. proteins, sterols and peptides, either intercalate into or loosely attach to the bilayer. We applied a molecular dynamics simulation method to study membrane systems at various levels of compositional complexity. The studies were started from simple lipid bilayers containing a single type phosphatidylcholine (PC) and water molecules (PC bilayers). As a next step, cholesterol (Chol) molecules were introduced to the PC bilayers (PC-Chol bilayers). These studies provided detailed information about the structure and dynamics of the membrane/water interface and the hydrocarbon chain region in bilayers built of various types of PCs and Chol. This enabled studies of membrane systems of higher complexity. They included the investigation of an integral membrane protein in its natural environment of a PC bilayer, and the antibacterial activity of magainin-2. The latter study required the construction of a model bacterial membrane which consisted of two types of phospholipids and counter ions. Whenever published experimental data were available, the results of the simulations were compared with them.
10
Content available remote

Patterning of Quantum Dots by Dip-Pen and Polymer Pen Nanolithography

75%
Biswas S., Brinkmann F., Hirtz M., Fuchs H.
|
EN
We present a direct way of patterning CdSe/ ZnS quantum dots by dip-pen nanolithography and polymer pen lithography. Mixtures of cholesterol and phospholipid 1,2-dioleoyl-sn-glycero-3 phosphocholine serve as biocompatible carrier inks to facilitate the transfer of quantum dots from the tips to the surface during lithography. While dip-pen nanolithography of quantum dots can be used to achieve higher resolution and smaller pattern features (approximately 1 μm), polymer pen lithography is able to address intermediate pattern scales in the low micrometre range. This allows us to combine the advantages of micro contact printing in large area and massive parallel patterning, with the added flexibility in pattern design inherent in the DPN technique.
11
Content available remote

Molecular modelling of membrane activity of amphotericin B, a polyene macrolide antifungal antibiotic

75%
Baginski M., Sternal K., Czub J., Borowski E.
Acta Biochimica Polonica
|
2005
|
vol. 52
|
issue 3
655-658
EN
Amphotericin B (AmB) is a well known polyene macrolide antibiotic used to treat systemic fungal infections. Despite its toxicity AmB is still regarded as a life-saving drug. The lack of adequate knowledge of the AmB mechanism of action is a serious obstacle to efficient development of new less toxic derivatives. Complementary to various experimental approaches, computational chemistry methods were used to study AmB mechanism of action. A programme lasting for a decade, that was run by our group covered studies of: i) molecular properties of AmB and its membrane targets, ii) structure and properties of AmB membrane channels, and iii) interaction of AmB with the membrane.
12
Publication available in full text mode
Content available

Assessment of Role of Job Components and Individual Parameters on the Raised Blood Pressure in a Noisy Industry

75%
Abbasi M., Farhang-Dehghan S., Yazdanirad S., Mehri A., Kolahdouzi M., Fallah Madvari R., Akbarzadeh A., Ghaljahi M., Abbasi M., Farhang-Dehghan S., Yazdanirad S., Mehri A., Kolahdouzi M., Fallah Madvari R., Akbarzadeh A., Ghaljahi M.
Archives of Acoustics
|
2019
|
vol. 44
|
issue 3
13
Content available remote

Conjugated linoleic acids regulate triacylglycerol and cholesterol concentrations in macrophages/foam cells by the modulation of CD36 expression

75%
Stachowska E., Baskiewicz M., Marchlewicz M., Czupryńska K., Kaczmarczyk M., Wiszniewska B., Machaliński B., Chlubek D.
Acta Biochimica Polonica
|
2010
|
vol. 57
|
issue 3
379-384
EN
Atherosclerosis is an inflammatory disease characterised by the accumulation of lipids and their metabolites in the artery wall. During inflammation circulating LDL are taken up by macrophages through two major scavenger receptors: CD36 and scavenger receptor A (SRA). Fatty acids that are common in food, e.g. linoleic acid and n-3 unsaturated fatty acids can modulate expression of CD36 on the macrophage surface. Conjugated linoleic acid isomers (CLA) that originate from the human diet, have demonstrated antiatherogenic properties in several experiments. Animal study evidenced that CLA could induce resolution of plaque by activation of peroxisome proliferator activated receptors and down-regulation of pro-inflammatory genes. Less unequivocal results were obtained in human studies (on the CLA effects on the inflammatory process). Therefore in this study we investigated the influence of CLA on CD36 expression and lipid accumulation in human macrophages. Macrophages were incubated with 30 µM cis-9,trans-11 CLA, trans-10,cis-12 CLA or linoleic acid for 48 h. After that, expression of CD36 as well as accumulation of lipids were measured by flow cytometry, microscopy and a spectroscopic method. We demonstrate that both cis-9,trans-11 C 18:2 CLA and linoleic acid slightly elevated expression of CD36, whereas second isomer - trans-10,cis-12 CLA - did not. Nevertheless, only trans-10,cis-12 CLA triggered delipidation of macrophages, that is decreased triacylglycerols concentration. Also in human adipocytes, trans-10,cis-12 CLA causes cell delipidation by reduction of PPAR receptor expression. We propose a similar mechanism for human macrophages/foam cells.
14
Publication available in full text mode
Content available

Dwie twarze cholesterolu: znaczenie fizjologiczne i udział w patogenezie wybranych schorzeń

71%
Użarowska M., Surman M., Janik M.
Kosmos
|
2018
|
vol. 67
|
issue 2
375-390
PL
Cholesterol to cząsteczka zbudowana z 17-węglowej struktury cyklopentanoperhydrofenantrenu i dołączonego do niej 6-węglowego łańcucha bocznego, klasyfikowana jako alkohol steroidowy ze względu na obecność pojedynczej grupy hydroksylowej. Główną funkcją cholesterolu jest zależna od temperatury modulacja płynności błon komórkowych. Duża ilość cholesterolu występuje w nanodomenach błonowych (tratwach lipidowych i kaweolach), które pełnią ważną rolę w procesie endocytozy i przekaźnictwie międzykomórkowym. Ponadto, jest on prekursorem hormonów steroidowych produkowanych przez gonady i korę nadnerczy oraz warunkuje właściwy przebieg rozwoju embrionalnego. Poza pełnieniem istotnej roli fizjologicznej, cholesterol może przyczyniać się do rozwoju wielu stanów patologicznych, wynikających zarówno z nagromadzenia jego cząsteczek w ustroju, jak i zaburzeń ich metabolizmu. Jego udział opisano m.in. w rozwoju schorzeń neurodegeneracyjnych, chorób układu krążenia, chorób nerek oraz chorób nowotworowych. Obecnie prowadzone badania zmierzają do opracowania nowych strategii terapeutycznych, pozwalających na skuteczniejszą i bezpieczniejszą kontrolę poziomu cholesterolu i regulację jego metabolizmu, oraz mających na celu wykorzystanie cholesterolu jako składnika nowych, skuteczniejszych leków.
EN
Cholesterol is a molecule build of 17-carbon cyclopentano-perhydro-phenanthrene structure and 6- carbon side chain, classified as steroid alcohol due to the presence of a single hydroxyl group. The main function of cholesterol is temperature-dependent modulation of cell membrane liquidity. Large amounts of cholesterol are found in membrane nanodomains (lipid rafts and caveolae) that are essential for endocytosis and intercellular signaling. Moreover, cholesterol is a substrate in steroid hormones biosynthesis in gonads and adrenal glands, and determines the proper course of embryonic development. Besides its physiological role, cholesterol may contribute to pathogenesis of different diseases, resulting from its accumulation in the system or from metabolic disorders. The significance of cholesterol has already been described in several neurodegenerative disorders, cardiovascular and renal diseases, and in cancer. Therefore, current research focus on providing some new therapeutic strategies, allowing for cholesterol level control, regulation of its metabolism, or for using cholesterol molecules as effective drug component.
15
Publication available in full text mode
Content available

Compound heterozygous LDLR variant in severely affected familial hypercholesterolemia patient

63%
Al-Allaf F., Alashwal A., Abduljaleel Z., Taher M., Bouazzaoui A., Abalkhail H., Al-Allaf A., Athar M.
Acta Biochimica Polonica
|
2017
|
vol. 64
|
issue 1
75-79
EN
Familial hypercholesterolemia (FH) is most commonly caused by mutations in the LDL receptor (LDLR), which is responsible for hepatic clearance of LDL from the blood circulation. We described a severely affected FH proband and their first-degree blood relatives; the proband was resistant to statin therapy and was managed on an LDL apheresis program. In order to find the causative genetic variant in this family, direct exon sequencing of the LDLR, APOB and PCSK9 genes was performed. We identified a compound heterozygous mutation in the proband with missense p.(W577C) and frameshift p.(G676Afs33) variants at exons 12 and 14 of the LDLR gene respectively. DNA sequencing of LDLR gene from the parents demonstrated that the missense variant was inherited from the mother and frameshift variant was inherited from the father. The frameshift variant resulted in a stop signal 33 codons downstream of the deletion, which most likely led to a truncated protein that lacks important functional domains, including the trans-membrane domain and the cytoplasmic tail domain. The missense variant is also predicted to be likely pathogenic and affect EGF-precursor homology domain of the LDLR protein. The segregation pattern of the variants was consistent with the lipid profile, suggesting a more severe FH phenotype when the variants are in the compound heterozygous state. The finding of a compound heterozygous mutation causing severe FH phenotype is important for the genotype-phenotype correlation and also enlarges the spectrum of FH-causative LDLR variants in the Arab population, including the Saudi population.
16
Content available remote

Biophysical changes induced by cholesterol on phosphatidylcholine artificial biomembranes containing alamethicin oligomers

63%
Cernescu A., Luchian T.
Open Physics
|
2006
|
vol. 4
|
issue 2
155-167
EN
Cholesterol is an important constituent of eukaryotic cell membranes, whose interaction with phospholipids leads to a broad range of biological roles, such as: maintenance of proper fluidity, formation of raft domains, reduction of passive permeability of various chemical species through the bilayer (e.g., glucose, glycerol, K+, Na+ and Cl− ions), and increased mechanical strength of the membrane. In this work we studied an interesting paradigm, as to whether cholesterol-containing phosphatidylcholine biomembranes influence the kinetics and transport features of alamethicin oligomers embedded into it. We demonstrate that moderate relative amounts of cholesterol increase the electrical conductance of various sub-conductance states of the alamethicin oligomer, caused probably by a non-monotonic change in the lumped dipole moment of the biomembrane. Our data suggest that biomembrane stiffness caused by cholesterol, visibly modifies the association-dissociation rates of alamethicin oligomerization in the biomembrane. Moreover, increasing concentrations of cholesterol seem to lead to more stable intermediate alamethicin oligomers. We show that in the presence of cholesterol, as the diameter of the alamethicin oligomer increases, so does the time of another monomer to get picked up. These results brings into focus the interesting issue of how oligomerization of proteins affects their interaction affinities for membrane-based lipids.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.