Evaluation of real-life dosing of oral medicines with respect to fluid and food intake in a Dutch-speaking population.

WHAT IS KNOWN AND OBJECTIVE: Oral drug administration is the most preferred route of drug administration. For some specific classes of drugs, recommendations regarding the intake of the drug product are provided by and approved in the summary of product characteristics (SmPC) after testing the oral drug product in clinical trials under strict and predefined conditions. The aim of this study was to investigate how certain classes of medicines are taken in a "real-life" setting in terms of concomitant fluid and food intake by a Dutch-speaking population in Flanders (Belgium). The outcome of this study was comprehensively discussed with literature data to evaluate the positive or negative consequences of their drug intake in daily life. METHODS: A retrospective and non-interventional study was set up by means of questionnaires completed by two different groups: children (ie 0-15 years) and (young) adults (ie 16 years and older). RESULTS AND DISCUSSION: In children, the co-administered volume increases with age because of a gradual switch from liquids to solid dosage forms. In adults, water was the most selected co-administered fluid and the preferred volume of intake was a half glass of liquid. WHAT IS NEW AND CONCLUSION: Results of the surveys clearly indicated that the majority of all participants took their medication with a sip or half glass of water. However, this was not the case for the youngest children, as their preferred formulations were liquids (eg solutions, suspensions) which do not require any extra intake of liquid. In the case of specific classes of drugs, real-life intake can still be improved, suggesting that the pharmacist's advice has an important influence on their administration of medicines.

A mouse model for Zellweger syndrome.

The cerebro-hepato-renal syndrome of Zellweger is a fatal inherited disease caused by deficient import of peroxisomal matrix proteins. The pathogenic mechanisms leading to extreme hypotonia, severe mental retardation and early death are unknown. We generated a Zellweger animal model through inactivation of the murine Pxr1 gene (formally known as Pex5) that encodes the import receptor for most peroxisomal matrix proteins. Pxr1-/- mice lacked morphologically identifiable peroxisomes and exhibited the typical biochemical abnormalities of Zellweger patients. They displayed intrauterine growth retardation, were severely hypotonic at birth and died within 72 hours. Analysis of the neocortex revealed impaired neuronal migration and maturation and extensive apoptotic death of neurons.

[alpha-Oxidation of 3-methyl-branched fatty acids: unraveling of a pathway]. / alpha-Oxidatie van 3-methylvertakte vetzuren: ontrafeling van een pathway.

Peroxisomes have an important role in lipid metabolism e.g. beta-oxidation of long and very long chain fatty acids, 2-methyl-branched fatty acids, dicarboxylic fatty acids, prostanoids and bile acid intermediates, and synthesis of ether lipids. Also the process of alpha-oxidation of 3-methyl-branched fatty acids, with phytanic acid (3,7,11,15-tetramethylhexadecanoic acid) as the best known example, occurs in peroxisomes. alpha-Oxidation is a process in which fatty acids are shortened by one carbon atom. The alpha-oxidation sequence of 3-methyl-branched fatty acids starts with an activation to the corresponding CoA-ester. Subsequently this acyl-CoA-ester undergoes a 2-hydroxylation by the peroxisomal phytanoyl-CoA hydroxylase (PAHX). In a third step the peroxisomal 2-hydroxyphytanoyl-CoA lyase (2-HPCL) splits the carbon carbon bond of the 2-hydroxy-intermediate into a 2-methyl(n-1)aldehyde and formyl-CoA, which is subsequently converted to formate and CO2. Finally the aldehyde is dehydrogenated by an aldehyde dehydrogenase to the corresponding acid, which, after its conversion to the acyl-CoA ester, can be a substrate for beta-oxidation. 2-HPCL is the first thiamine pyrophosphate dependent peroxisomal enzyme in mammals. Apart from 2-hydroxy-3-methylacyl-CoAs also 2-hydroxyacyl-CoAs are substrates for this enzyme. This indicates that the 2-hydroxy function but not the 3-methyl function of acyl-CoA esters is needed for 2-HPCL-activity. Long and very long chain 2-hydroxy fatty acids are constituents of brain cerebrosides and sulfatides, which mainly occur in myelin.

Evidence for the importance of iron in the alpha-oxidation of 3-methyl-substituted fatty acids in the intact cell.

Preincubation of isolated rat hepatocytes with desferrioxamine or o-phenanthroline, two iron-specific chelators, strongly suppressed the CO2-production from the alpha-oxidation of 3-methylmargaric acid, whereas the beta-oxidation of 2-methylpalmitic acid, palmitic acid, trihydroxycoprostanic acid and the conversion of formic acid to CO2 were not affected. When, after the initial preincubation with the chelators and prior to the addition of 3-methylmargaric acid, iron-saturated transferrin and Fe3+ were added, a partial restitution of the CO2-production rates was obtained. These facts provide further evidence for the importance of iron in the alpha-oxidation of 3-methyl-substituted fatty acids.

2-methylacyl racemase: a coupled assay based on the use of pristanoyl-CoA oxidase/peroxidase and reinvestigation of its subcellular distribution in rat and human liver.

Because of the 2S-methyl-stereospecificity of the acyl-CoA oxidases acting on the CoA esters of 2-methyl-branched fatty carboxylates such as pristanic acid and the side chain of trihydroxycoprostanic acid (Van Veldhoven P.P., Croes K., Asselberghs S., Herdewijn P. and Mannaerts G.P. (1996) FEBS Lett. 388, 80-84), naturally occurring 2R-pristanic acid and 25R- (corresponding to 2R in the side chain) trihydroxycoprostanic acid, after activation to their CoA-esters, need to be racemized to the S-isomers before they can be degraded by peroxisomal beta-oxidation. A coupled assay to measure 2-methyl-acyl racemases was developed by using purified rat pristanoyl-CoA oxidase. Upon incubation of rat and human liver homogenates with 2R-methyl-pentadecanoyl-CoA, the formed 2S-methyl isomer was desaturated by an excess of added oxidase and the concomitant production of hydrogen peroxide was monitored by means of peroxidase in the presence of a suitable hydrogen donor. Application of this assay to subcellular fractions of rat liver revealed the presence of racemase activity not only in mitochondria, as described by Schmitz W., Albers C., Fingerhut R. and Conzelmann E. (Eur. J. Biochem. (1995) 231, 815-822), but also in peroxisomes and cytosol. A similar distribution was seen in human liver. In rat the highest activities were found in liver, followed by Harderian gland, kidney and intestinal mucosa.

Production of formyl-CoA during peroxisomal alpha-oxidation of 3-methyl-branched fatty acids.

alpha-Oxidation of 3-methyl-substituted fatty acids was studied in purified rat liver peroxisomes. The experiments revealed that formyl-CoA is formed during the alpha-oxidation process. The amount of formyl-CoA found constituted 2-5% of the amount of formate formed. Under the conditions used, no activation of exogenously added formate occurred in purified peroxisomes, whereas 95.5% of added synthetic formyl-CoA was converted to formate. These data indicate that during alpha-oxidation first formyl-CoA is formed, which is then hydrolysed to formate.

Formation of a 2-methyl-branched fatty aldehyde during peroxisomal alpha-oxidation.

In the final reaction of peroxisomal alpha-oxidation of 3-methyl-branched fatty acids a 2-hydroxy-3-methylacyl-CoA intermediate is cleaved to formyl-CoA and a hitherto unidentified product. The release of formyl-CoA suggests that the unidentified product may be a fatty aldehyde. When purified rat liver peroxisomes were incubated with 2-hydroxy-3-methylhexadecanoyl-CoA 2-methylpentadecanal was indeed formed. The production rates of formyl-CoA (measured as formate) and of the aldehyde were in the same range. While the production of formate remained unaltered in the presence of NAD+, the amount of 2-methylpentadecanal was decreased, which was accompanied by the formation of 2-methylpentadecanoic acid. These data indicate that (1) during alpha-oxidation the 2-hydroxy-3-methylacyl-CoA is cleaved to a 2-methyl-branched aldehyde and formyl-CoA and (2) liver peroxisomes are capable of converting this aldehyde to a 2-methyl-branched fatty acid.

Neonatal seizures and severe hypotonia in a male infant suffering from a defect in peroxisomal beta-oxidation.

In this paper, we describe a baby male born to healthy non-consanguineous parents presenting at birth with hypotonia and seizures. Additional salient clinical features included the development of glaucoma, the absence of significant facial dysmorphism and the absence of liver enlargement or renal cysts. The patient died at the age of 3 months. At autopsy, liver fibrosis and kidney glomerulosclerosis were noted. Neuropathological findings included pachygyria of the olivary nuclei and cerebellar neuronal heterotopias. There was no evidence for a demyelinating process. Biochemically, the patient was found to have elevated plasma levels of very-long-chain fatty acids (VLCFA) and abnormal bile acid intermediates, whereas other indicators of peroxisomal function (plasmalogen biosynthesis and plasma pipecolic acid) were normal. Catalase staining of a liver biopsy specimen revealed peroxisomes to be present in normal numbers, although some were abnormally large. Trilamellar inclusions typical of a peroxisomal fatty acid oxidation defect were present in macrophages. Indeed, beta-oxidation of the very-long-chain fatty acid hexacosanoic acid (C26:0) was found to be strongly deficient. Fatty acyl-CoA oxidase activity in the patient's liver was normal, however. Furthermore immunocytochemical studies using antibodies against acyl-CoA oxidase, bifunctional protein and peroxisomal thiolase, revealed the normal localization of all three enzyme proteins within the peroxisomes. We suggest that our patient has a selective peroxisomal beta-oxidation defect, a recently identified heterogeneous group of early-onset peroxisomal disorders distinct from the Zellweger syndrome and other generalized peroxisomal disorders.

Aminotriazole is a potent inhibitor of alpha-oxidation of 3-methyl-substituted fatty acids in rat liver.

The production of CO2 and formate in isolated rat hepatocytes incubated in the presence of 3-methyl[1-14C]margaric acid was investigated. Production rates of formate were approximately 4-fold lower than those of CO2. Aminotriazole (3-amino-1, 2, 4-triazole), an irreversible inhibitor of catalase, potently suppressed alpha-oxidation of 3-methylmargaric acid, whereas beta-oxidation of palmitate, 2-methylpalmitate and trihydroxycoprostanic acid and conversion of exogenously added formate to CO2 were not or only slightly affected. This shows that aminotriazole is not only an inhibitor of catalase, but also of alpha-oxidation of 3-methyl-substituted fatty acids.

Peroxisomal lipid degradation via beta- and alpha-oxidation in mammals.

Peroxisomal beta-oxidation is involved in the degradation of long chain and very long chain fatty acyl-(coenzyme A)CoAs, long chain dicarboxylyl-CoAs, the CoA esters of eicosanoids, 2-methyl-branched fatty acyl-CoAs (e.g. pristanoyl-CoA), and the CoA esters of the bile acid intermediates di- and trihydroxycoprostanic acids (side chain of cholesterol). In the rat, straight chain acyl-CoAs (including the CoA esters of dicarboxylic fatty acids and eicosanoids) are beta-oxidized via palmitoyl-CoA oxidase, multifunctional protein-1 (which displays 2-enoyl-CoA hydratase and L-3-hydroxyacyl-CoA dehydrogenase activities) and peroxisomal thiolase. 2-Methyl-branched acyl-CoAs are degraded via pristanoyl-CoA oxidase, multifunctional protein-2 (MFP-2) (which displays 2-enoyl-CoA hydratase and D-3-hydroxyacyl-CoA dehydrogenase activities) and sterol carrier protein-X (SCPX; displaying 2-methyl-3-oxoacyl-CoA thiolase activity). The side chain of the bile acid intermediates is shortened via one cycle of beta-oxidation catalyzed by trihydroxycoprostanoyl-CoA oxidase, MFP-2 and SCPX. In the human, straight chain acyl-CoAs are oxidized via palmitoyl-CoA oxidase, multifunctional protein-1, and peroxisomal thiolase, as is the case in the rat. The CoA esters of 2-methyl-branched acyl-CoAs and the bile acid intermediates, which also possess a 2-methyl substitution in their side chain, are shortened via branched chain acyl-CoA oxidase (which is the human homolog of trihydroxycoprostanoyl-CoA oxidase), multifunctional protein-2, and SCPX. The rat and the human enzymes have been purified, cloned, and kinetically and stereochemically characterized. 3-Methyl-branched fatty acids such as phytanic acid are not directly beta-oxidizable because of the position of the methyl-branch. They are first shortened by one carbon atom through the a-oxidation process to a 2-methyl-branched fatty acid (pristanic acid in the case of phytanic acid), which is then degraded via peroxisomal beta-oxidation. In the human and the rat, alpha-oxidation is catalyzed by an acyl-CoA synthetase (producing a 3-methylacyl-CoA), a 3-methylacyl-CoA 2-hydroxylase (resulting in a 2-hydroxy-3-methylacyl-CoA), and a 2-hydroxy-3-methylacyl-CoA lyase that cleaves the 2-hydroxy-3-methylacyl-CoA into a 2-methyl-branched fatty aldehyde and formyl-CoA. The fatty aldehyde is dehydrogenated by an aldehyde dehydrogenase to a 2-methyl-branched fatty acid while formyl-CoA is hydrolyzed to formate, which is then converted to CO2. The activation, hydroxylation and cleavage reactions, and the hydrolysis of formyl-CoA are performed by peroxisomal enzymes; the aldehyde dehydrogenation remains to be localized whereas the conversion of formate to CO2 occurs mainly in the cytosol.

Accumulation and impaired in vivo metabolism of di- and trihydroxycholestanoic acid in two patients.

Two patients with a suspected peroxisomal disorder on the basis of neurological, craniofacial, hepatological and other abnormalities were studied. The phenotype of both girls was remarkably similar from birth until age 1.5 yr. Detailed studies in plasma revealed normal plasma very-long-chain fatty acids but the presence of di- and trihydroxycholestanoic acids and the C29-dicarboxylic bile acid, all known to occur in plasma from Zellweger patients. These results suggest an isolated defect in the peroxisomal beta-oxidation of the side chains of the cholestanoic acids. Activation of trihydroxycholestanoic acid and beta-oxidation of trihydroxycholestanoyl-CoA, measured in a liver biopsy, were normal, however, as was the peroxisomal beta-oxidation of palmitate. Although the molecular defect remains unknown, the results stress the importance of performing multiple analyses in any patient suspected to suffer from a peroxisomal disorder and indicate that screening for peroxisomal disorders based upon analysis of only plasma very long chain fatty acids with or without analysis of erythrocyte plasmalogen levels, may be inadequate.

Hepatic alpha-oxidation of phytanic acid. A revised pathway.

Synthetic 3-methyl-branched chain fatty acids were used to decipher the breakdown of phytanic acid. Based on results obtained in intact or permeabilized rat hepatocytes, rat liver homogenates or subcellular fractions, a revised alpha-oxidation pathway is proposed which appears to be functioning in man as well. In a first step, the 3-methyl-branched chain fatty acid is activated by an acyl-CoA synthetase. This reaction requires CoA, ATP and Mg2+. Subsequently, the acyl-CoA ester is hydroxylated at position 2 by a peroxisomal dioxygenase. This step is dependent on alpha-oxoglutarate, ascorbate (or glutathione), Fe2+ and O2. The 2-hydroxy-3-methylacyl-CoA intermediate is cleaved by a peroxisomal lyase to formyl-CoA and a 2-methyl-branched fatty aldehyde. Formyl-CoA is (partly enzymically) hydrolyzed to formate, which is then converted, most likely in the cytosol, to CO2. In the presence of NAD+, the aldehyde is dehydrogenated to a 2-methyl-branched fatty acid, presumably by a peroxisomal aldehyde dehydrogenase. This acid can--after activation--be degraded via a D-specific peroxisomal beta-oxidation system.

Effects of electrical stimulation, followed by moderate cooling, on meat quality characteristics of veal Longissimus dorsi.

Three groups of male Friesian veal calves (in total, 92) were slaughtered in separate series. Within each group, a subgroup (selected on the basis of blood characteristics determined 1 week ante mortem) was electrically stimulated immediately after bleeding (64 s-Mitab® Low voltage unit). Carcasses were transferred ca. 25 min post mortem (pm) to a cooler at 6°C and ca 2 h pm to a cooler at 3°C. Electrical stimulation (ES) increased brightness and, to a lesser extent, yellowness, of the freshly cut surface (6th rib Longissimus dorsi, 24 h pm) but resulted also in a diminished water-holding capacity (WHC) of the veal meat. The effect of ES on tenderness (Warner-Bratzler shear force, 48 h pm) is positive for two of the three groups but negative for the third. This indicates that ES probably results in two opposite effects on tenderness-'toughening', as a result of the sarcomere shortening which occurred in all three groups, and 'tenderizing', as a result of microscopical fibre disruption. Our data indicate that disadvantages of ES may outweigh advantages when followed by moderate cooling.

Omega-3 fatty acids in pig nutrition: Implications for the intrinsic and sensory quality of the meat.

Seventy-eight hybrid pigs (Piétrain × Seghers hybrid cross, 38 barrows and 40 gilts) were fed ad libitum diets, containing either 0.4%, 0.7% or 1.0% α-linolenic acid (C18:3n-3), originating from linseed. The variation in polyunsaturated fatty acid content in the feed (1.19%, 1.52% and 1.88%, respectively) was mainly attributed to variations in α-linolenic acid content. Meat quality evaluated by physical measurements (pH, light scattering, conductivity, colour, light reflection, tenderness, water holding capacity) was not influenced, to any significant extent, by the fatty acid composition of the feed. A subjective judgement of cohesiveness revealed no abnormalities. Dietary fat source, sex and intramuscular fat (IMF) level affected the fatty acid pattern of the IMF. The α-linolenic content in the IMF increased from 1.2% to 2.3% for the barrows and from 1.4% to 2.9% for the gilts with increasing αlinolenic acid content in the feed. A multiple paired comparison test for taste, tenderness and juiciness on 45 meat samples (M. longissimus thoracis) revealed no significant differences among the feed groups.

The relationship between carcass, meat and eating quality of three pig genotypes.

The relation between the intrinsic carcass and meat quality and the organoleptical characteristics of three genotypes of pigs was studied. In total 411 pigs, consisting of 121 BL-genotype pigs, 115 hybrids (Seghers Hybrid) and 175 Large White-genotype pigs, were screened. Slaughter day and genetic background had a great impact on the intrinsic meat quality parameters. The factor 'slaughter day' implies the stunning method besides the total specific transport and slaughter conditions. Whatever the genetic background is, halothane susceptibility is obviously the crucial factor. Selection against the halothane gene positively influences the intrinsic and sensory meat quality parameters. This study also suggests that an increase in the intramuscular fat content, if desirable in the interest of the sensory meat quality, can be achieved without deterioration of the zoo-technical performance and the carcass quality of the pigs.

Eating quality of European beef assessed at five research institutes.

Loin steaks from 10 animals (five of each of two types) from each of eight European countries were assessed for eating quality at five institutes in Denmark, Ireland, England, France and the Federal Republic of Germany. All panels found wide variation in eating quality and many of the steaks were unacceptably tough. Although attempts to relate quality to production factors were often confounded, differences in post-slaughter handling, particularly between producing countries, dominated eating quality. Breed, sex, age or fatness had relatively little influence on eating quality in this trial. A common eight-category scale of tenderness/toughness was used in addition to each institute's usual descriptive scales for tenderness, flavour, juiciness and overall acceptability, employing four to eleven categories. Within panels, attribute scores were not independent and tenderness and flavour in combination were the best predictors of overall acceptability. Between panels, tenderness was highly interrelated, flavour and juiciness poorly interrelated. These findings, together with estimates of each panel's discrimination and the variation between individual assessors, are discussed in relation to standardisation and equivalence of sensory methodology.

Comparison of chemical composition of meat determined at eight laboratories.

Sixteen minced samples of lean beef M. semimembranosus and M. gracilis were analysed for nitrogen, fat, moisture, collagen, ash and pH using recommended procedures in eight European Communitie' (EC) meat research laboratories. Differences between replicate determinations within laboratories were often larger than suggested in reference methods although they were smaller than the differences between laboratories. Moisture and pH were determined most consistently, collagen least consistently.

Beef quality assessed at European research centres.

Loin steaks and cubes of M. semimembranosus from eight (12 month old) Galloway steers and eight (16-18 month old) Charolais cross steers raised in England and from which the meat was conditioned for 2 or 10 days, were assessed in research centres in Belgium, Denmark, England, France, the Federal Republic of Germany, Ireland, Italy and the Netherlands. Laboratory panels assessed meat by grilling the steaks and cooking the cubes in casseroles according to local custom using scales developed locally and by scales used frequently at other research centres. The meat was mostly of good quality but with sufficient variation to obtain meaningful comparisons. Tenderness and juiciness were assessed most, and flavour least, consistently. Over the 32 meats, acceptability of steaks and casseroles was in general compounded from tenderness, juiciness and flavour. However, when the meat was tough, it dominated the overall judgement; but when tender, flavour played an important rôle. Irish and English panels tended to weight more on flavour and Italian panels on tenderness and juiciness. Juciness and tenderness were well correlated among all panels except in Italy and Germany. With flavour, however, Belgian, Irish, German and Dutch panels ranked the meats similarly and formed a group distinct from the others which did not. The panels showed a similar grouping for judgements of acceptability. French and Belgian panels judged the steaks from the older Charolais cross steers to have more flavour and be more juicy than average and tended to prefer them. Casseroles from younger steers were invariably preferred although the French and Belgian panels judged aged meat from older animals equally acceptable. These regional biases were thought to be derived mainly from differences in cooking, but variations in experience and perception of assessors also contributed.

Magnetic resonance imaging of extrapontine lesions in central pontine myelinolysis.

A rare case of central pontine myelinolysis and associated extrapontine myelinolysis is presented. The MR findings confirmed the observations reported in recent papers.

How often did Belgian physicians co-prescribe tamoxifen with strong CYP2D6 inhibitors over the last 6 years?

AIMS: Tamoxifen is widely used in the treatment of breast cancer. It is a pro-drug metabolized to the more active endoxifen through CYP2D6. Concomitant intake of CYP2D6 inhibitors results in lower endoxifen levels and could influence efficacy. The objective of this study was to evaluate the evolution of co-prescription of tamoxifen and CYP2D6 inhibitors in Belgium. METHODS: Data were retrieved from the Pharmanet database of the National Institute for Health and Disability Insurance for the period January 2006-December 2009. For the analysis of the evolution of the co-prescription, the period was divided in subperiods of 2 months. The category tamoxifen+CYP2D6 inhibitor was defined as women who were delivered tamoxifen and a CYP2D6 inhibitor in that subperiod. The results were validated on the period December 2011-May 2012. RESULTS: The percentage of co-prescription decreased over time for the strong CYP2D6 inhibitors and increased for the weak CYP2D6 inhibitor, with these trends persisting in 2012. Tamoxifen and CYP2D6 inhibitors were mostly prescribed by general practitioners and gynaecologists and by general practitioners and psychiatrists, respectively. DISCUSSION: This study shows that a proportion of women taking tamoxifen in Belgium are prescribed a strong CYP2D6 inhibitor, which could affect tamoxifen efficacy. Over time, the concomitant intake decreased. Paroxetine was the most prescribed strong CYP2D6 inhibitor. Venlafaxine, a weak CYP2D6 inhibitor, was prescribed more often. This study also shows that tamoxifen and the CYP2D6 inhibitors are not only prescribed by physicians specialized in breast cancer; therefore, all physicians should be aware of this interaction.