[Laboratory diagnosis of a rare congenital neurodegenerative disease: cerebrotendinous xanthomatosis]. / Egy ritka, veleszületett neurodegeneratív betegség: a cerebrotendinosus xanthomatosis laboratóriumi diagnosztikája.

Cerebrotendinous xanthomatosis is a rare neurodegenerative disease characterized by the accumulation of cholesterol and cholestanol in the brain and the tendons caused by mutations of the gene encoding sterol 27-hydroxylase (CYP27A1), which is involved in bile acid synthesis. The diagnosis is often missed and delayed because of the variable clinical presentation of the disease. Blood testing for cerebrotendinous xanthomatosis is routinely performed using gas chromatography-mass spectrometry measurement of elevated cholestanol level, and the diagnosis is confirmed by molecular genetic analysis. Early recognition and initiation of chenodeoxycholic acid therapy with hydoxymethyl­glutaryl­Coenzyme-A reductase inhibitors is critical to prevent irreversible neurological damage and permanent disability. The authors summarize the current knowledge about the pathomechanism, laboratory diagnosis and therapeutic options of cerebrotendinous xanthomatosis.

Effect of apolipoprotein E genotypes on the efficacy of ezetimibe monotherapy in patients with statin induced adverse effects.

OBJECTIVE: The aim of this study was to clarify the effect of Apolipoprotein E (ApoE) polymorphism on the efficacy of cholesterol absorption inhibitor ezetimibe monotherapy on lipid parameters. METHODS: 63 hyperlipidemic patients with statin induced adverse effects were involved in the study. We examined the effect of 10 mg/day ezetimibe treatment on lipid levels after 3, 6 and 12 months of treatment in patients on a diet of only different ApoE genotypes. RESULTS: Three months of ezetimibe treatment significantly decreased the total cholesterol (TC) (-10.1%), low-density lipoprotein (LDL-C) (-12.0%) (p < 0.001) and triglyceride (Tg) (-8%) levels (p < 0.05). After 6 and 12 months of treatment reduction in TC, LDL-C and Tg levels were even more pronounced. The genotype distribution of the patients were 2/2: 4.8%, 2/3: 7.9%, 3/3: 68.3%, 3/4: 19.0%. There were no patients with 2/4 and 4/4 genotypes. In patients with 2/3, 3/3 or 3/4 genotype, the ezetimibe treatment tended to be more effective on TC and LDL-C levels than in the 2/2 group, and the efficacy of ezetimibe on Tg levels were slightly better in 2/2 carriers compared to other patients. CONCLUSIONS: The ApoE genotype does not predict the efficacy of ezetimibe treatment on serum lipid parameters.

[Genetic background of the efficacy of cholesterol absorption. The role of Niemann-Pick C1-like 1 receptor and its genetic variations in lipid metabolism]. / A koleszterinfelszívódás hatékonyságának genetikai háttere. A Niemann-Pick C1-like-1 receptor és génvariációinak szerepe a lipidanyagcserében.

Niemann-Pick C1-like 1 is a sterol sensing domain-containing transmembrane protein that is highly expressed on the apical surface of absorptive enterocytes. Previous studies proved that this protein facilitates the movement of free cholesterol from the gut lumen into enterocytes. Biochemical studies showed that Niemann-Pick C1-like 1 is the target of ezetimibe, a potent cholesterol absorption inhibitor. Recent studies show that genetic variation in Niemann-Pick C1-like 1 may be responsible for the inter-individual variability observed in the rates of intestinal cholesterol absorption and the response to ezetimibe.

Benefits and difficulties in measuring HDL subfractions and human paraoxonase-1 activity during statin treatment.

Dyslipidaemia including decreased high density lipoprotein cholesterol concentration is one of several factors that have been implicated in increased cardiovascular risk. Since their introduction in the 1980s, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have emerged as the one of the best-selling class of medications to date, with numerous trials demonstrating powerful efficacy in preventing cardiovascular diseases. Although statins have been shown to modestly raise or not alter HDL-cholesterol, their effect on HDL subfractions and on HDL-associated enzymes including human paraoxonase-1 (PON1) has not yet been fully explored. This review summarizes the currently available data on the effect of statins on HDL subfractions and on PON1 activity with a particular emphasis on the clinical relevance of these effects. Moreover, methodological problems of HDL subfraction and PON1 activity determinations are also discussed.

Cyclodextrins found in enzyme- and heat-processed starch-containing foods.

Native and branched-type (glucosylated and maltosylated) cyclodextrins have been isolated and identified in different enzyme- and heat-processed starch-containing food products. Amylolytic enzyme-processed foods such as different beer samples, corn syrup of different dextrose equivalents, and thermally-processed food such as bread, contained minute amounts of different types of cyclodextrins. HPLC/MS Analyses of appropriately preconcentrated and purified food samples indicated the presence of parent beta- and gamma-cyclodextrins and all the three, alpha-, beta-, and gamma-branched cyclodextrins with different degrees of glycosylation. The data presented in this account are thought to be of practical importance in terms of both the analysis methods used for the cyclodextrins and the approval status of different cyclodextrin-containing food, cosmetic, and pharmaceutical products.

Retention index calculation without n-alkanes--the virtual carbon number.

For the fast gas chromatographic identification of separated components the retention index is still one of the most often used tools, although mass spectrometry is available in almost all analytical laboratories. For the calculation of the retention indices it is not necessary to use n-alkanes or any other homologous series. If the analyte contains some compounds, not necessarily belonging to a homologous series, with well-known retention indices those compounds can be used as index references and the index of the other compounds can be calculated as is done using n-alkanes. The only difference is that instead of the carbon number of the n-alkanes, virtual carbon numbers of the reference compounds should be used. The method of calculation, and the effect of this method of calculation on the reproducibility are discussed in this paper, and analyses of some halogenated compounds and marjoram oil are used as experimental examples.

Computer-aided subsite mapping of α-amylases.

Subsite mapping is a crucial procedure in the characterization of α-amylases (EC 3.2.1.1), which are extensively used in starch-based industries and in diagnosis of pancreatic and salivary glands disorders. A computer-aided method has been developed for subsite mapping of α-amylases, which substitutes the difficult, expensive, and time-consuming experimental determination of action patterns to crystal structures based energy calculations. Interaction energies between enzymes and carbohydrate substrates were calculated after short energy minimization by a molecular mechanics program. A training set of wild type and mutant amylases with known experimental action patterns of 13 enzymes of wide range of origin was used to set up the procedure. Calculations for training set resulted in good correlation in case of subsite binding energies (r(2)=0.827-0.929) and bond cleavage frequencies (r(2)=0.727-0.835). A set of eight novel barley amylase 1 mutants was used to test our model. Subsite binding energies were predicted with r(2)=0.502 correlation coefficient, while bond cleavage frequency prediction resulted in r(2)=0.538. Our computer-aided procedure may supplement the experimental subsite mapping methods to predict and understand characteristic features of α-amylases.