Ferritine : onderzoekingen over de opbouw en afbraak van deze stof in verband met zijn functie in het ijzermetabolisme

De duitse farmacoloog Schmiedenberg was de eerste die in 1894 een ijzerhoudend eiwit beschreef dat geïsoleerd was uit varkenslever. Hij noemde dit ferratine. Zijn isolatie methode was echter dusdanig dat het hier geen zuiver eiwit betrof maar een mengsel van eiwitten en nucleïnezuren. In 1909 beschreef Scaffidi de bereiding uit varkenslever van een nucleoproteïne preparaat van de volgende samenstelling: 3, 5% Fe, 3, 3% P. Hierop voortbouwend hebben verschillende onderzoekers getracht om het nucleoproteïne ijzervrij in handen te krijgen, zonder veel succes echter. Een beter inzicht in de aard van het preparaat werd verkregen toen de probleemstelling door Laufberger werd omgedraaid. Deze auteur trachtte de eiwitijzer verbinding van contaminerend nucleïnezuur te bevrijden. Zijn eerste pogingen, waarbij van paardelever werd uitgegaan bleven zonder succes. Pas nadat de paardelever werd vervangen door paardemilt slaagde hij er in een ijzerhoudend eiwit te isoleren dat hij ferritine noemde. Dit ferritine bevatte 20% ijzer, betrokken op drooggewicht en het hoge ijzergehalte bracht Lauiberger er toe te veronderstellen dat ferritine betrokken zou zijn bij de opslag van ijzer in het lichaam. In dit verband was al eerder door Cook en Asher aangetoond dat in geval van snelle hemoglobine destructie in het lichaam. een ijzerhoudend pigment wordt gevormd in beenmerg, milt en lever, gepaard gaande met een ziektebeeld dat bekend staat onder de naam hemochromatosis. Na de publicatie van Laufberger in 1937 duurde het tot 1942 toen Granick de isolatie van ferritine opnieuw ter hand nam en de fysisch-chemische eigenschappen van ferritine aan een nader onderzoek onderwierp

Effects of therapy with lansoprazole on intestinal permeability and inflammation in young cystic fibrosis patients

Effects of therapy with lansoprazole on intestinal permeability and inflammation in young cystic fibrosis patients. Hendriks HJ, van Kreel B, Forget PP. Department of Paediatrics, University Hospital of Maastricht, Maastricht, The Netherlands. [email protected] BACKGROUND: Defective pancreatic bicarbonate secretion with low intestinal pH or intestinal inflammation of any origin increase intestinal permeability in cystic fibrosis (CF). METHODS: In this open study, the authors evaluated the effect of a proton-pump inhibitor on intestinal permeability and inflammation in 14 young, pancreatic-insufficient CF patients. Permeability was measured by a three-sugar permeability test before and after 1 year of lansoprazole use, and urinary nitric oxide (NO) oxidation products were assessed before and during that year as a marker of inflammation. RESULTS: After 1 year of lansoprazole use, median urinary recovery percentages changed from 2.5% to 1.7% (P = 0.064), from 24.9% to 24.5% (no significance), and from 10.5% to 11.1% (no significance) for lactulose, mannitol, and L-rhamnose, respectively. Despite the fact that the median urinary excretion ratios decreased from 0.108 to 0.083 (P = 0.03) and from 0.246 to 0.176 (P = 0.016) for lactulose and mannitol and for lactulose and rhamnose, respectively, they both remained increased. Median urinary NO products-to-creatinine ratios were 0.287 for CF patients before lansoprazole and 0.130 for healthy control participants (P = 0.002). Although there was a tendency toward a decrease in the NO products-to-creatinine ratio during treatment, this was not significant at the end point. CONCLUSIONS: Intestinal permeability is considerably increased in CF patients and is partly corrected after the use of a proton-pump inhibitor for 1 year, which may point to a harmful effect of the acid luminal contents on the tight junctional related paracellular permeability pathway. The start and end values for the NO products-to-creatinine ratio in CF patients were not significantly different, but were considerably increased when compared with control participants (P = 0.002)

Lipid, nitrogen, water and energy content of a single stool sample in healthy children and children with cystic fibrosis

Lipid, nitrogen, water and energy content of a single stool sample in healthy children and children with cystic fibrosis. Van den Neucker AM, Forget PP, van Kreel B. Department of Paediatrics, University Hospital Maastricht, P Debyelaan 25, 6229 HX Maastricht, The Netherlands. [email protected] To evaluate the usefulness of "single stool sample" analysis in the investigation of steatorrhoea instead of 72-h stool collection, we examined 57 stool samples of patients with cystic fibrosis (CF) while on pancreatic enzyme therapy and 29 stool samples of healthy children. We compared results of fat, nitrogen, water and energy content. Fat was determined by the method of Van de Kamer et al. and the Acid Steatocrit (AS) method, water by vacuum drying, nitrogen by the Dumas method and energy was obtained using a bomb calorimeter. Results (median) for CF patients and healthy controls were significantly different (P< or =0.0001) for fat respectively: 8.90 and 4.75/100 g wet weight (ww) stool as measured by the method of Van de Kamer et al. and 28.6% and 7.2% by the AS method. Energy results for energy were also significantly (P< or =0.0001) different: 742.96 and 549.32 kJ/100 g ww stool for CF patients and healthy controls respectively. Results of single stool sample water and nitrogen were similar in both groups. These results were comparable to those of a 3-day stool collection, as reported in the literature. CONCLUSION: Results from single stool samples yield clinically useful information concerning fat and energy. Single stool sample analysis is therefore useful for frequent monitoring of faecal fat and energ

Bioelectrical impedance measurements in patients with gastrointestinal disease: validation of the spectrum approach and a comparison of different methods for screening for nutritional depletion

Bioelectrical impedance measurements in patients with gastrointestinal disease: validation of the spectrum approach and a comparison of different methods for screening for nutritional depletion. Cox-Reijven PL, van Kreel B, Soeters PB. Department of Dietetics, University Hospital Maastricht, P Debyelaan 25, PO Box 5800, 6202 AZ Maastricht, Netherlands. [email protected] BACKGROUND: Bioelectrical impedance spectroscopy (BIS) may be of value in identifying patients with nutritional depletion. OBJECTIVE: The primary aim of the study was to assess the validity of BIS in patients with gastrointestinal disease. The secondary aim was to compare different screening methods for identifying nutritionally depleted patients. DESIGN: In 70 patients with gastrointestinal disease, BIS measurements were performed and fluid compartments were calculated from extrapolated resistance (R) values of extracellular (R(ECW)) and intracellular (R(ICW)) water based on mixture equations. Results were compared with total body water and ECW, which were measured by dilution methods. Patients were classified as depleted if their actual fat-free mass (FFM) was <90% of their ideal FFM (iFFM). Different screening approaches for depletion were compared: the impedance vector method and the resistance index (RI) in relation to iFFM (RI/iFFM). RESULTS: Total body water and ICW were largely underestimated (4 L) in the not-depleted patients but not in the depleted patients. In both groups, ECW was slightly overestimated (0.6-0.7 L). The critical frequency was 60% higher and the membrane capacitance was 40% lower in the depleted than in the not-depleted patients. The impedance vector method failed to identify depleted patients, whereas the proposed ratio at R(50) (R measured at 50 kHz) and R(inf) (R at infinite frequency) resulted in comparable sensitivity (86%) and specificity (73-80%). CONCLUSIONS: BIS measures of body fluids are influenced by the presence of depletion, probably because of alterations in the electric properties of the body at the cellular level. However, for screening purposes, the use of the ratio (L(2)/R)/iFFM at R(50) and R(inf) may be of valu

Improved steatocrit results obtained by acidification of fecal homogenates are due to improved fat extraction.Improved steatocrit results obtained by acidification of fecal homogenates are due to improved fat extraction.

Improved steatocrit results obtained by acidification of fecal homogenates are due to improved fat extraction. Tran M, Forget P, Van den Neucker A, van Kreel B. Department of Pediatrics, University Hospital of Maastricht, The Netherlands. Conflicting results have been reported on the value of the steatocrit as a screening test for steatorrhea. We recently modified the test procedure by fecal acidification with the hope of improving fat extraction and consequently the sensitivity of the test. The aim of the present study was to ascertain whether or not fecal acidification led to improved fat extraction by comparing the fat content of both fatty and solid layers obtained by centrifugation of 12 acidified (acid steatocrit) and unacidified (classical steatocrit) steatorrheal stool samples. The fat content of fatty and solid layers was evaluated using the semiquantitative (+ = 1, +2 = 2, +3 = 3) scoring system described by Drummey for the interpretation of the Sudan microscopic method for fecal fat. The fatty layers sum of scores for the 12 samples examined was 31 and 16 for the acid and classical steatocrit, respectively. The solid layers sum of scores for the 12 samples was 13 and 24 for the acid and classical steatocrit, respectively. Fat extraction from stool samples was significantly improved after fecal sample acidification (p < 0.005). Acid steatocrit results agreed better with chemically measured fecal fat than classical steatocrit results. We conclude that fecal acidification, by improving fat extraction, increases the reliability of the steatocrit method for the detection of steatorrhea

Measurement of total body water in children using bioelectrical impedance: a comparison of several prediction equations

Background: Body composition evaluation by bioelectrical impedance analysis in children makes use of different group-specific population-derived equations. The present study was conducted to attempt to validate the use of population-independent physical model-derived equations in children. Methods: The validity of bioelectrical impedance analysis for the measurement of total body water in children was evaluated by comparing results of two physical model-derived and two population-derived equations with those of deuterium dilution as reference method in a group of 38 heterogeneous children. Results: Means +/- standard deviation (in liters) for total body water measured with deuterium dilution and the physical model 1-derived equation were 18.4 +/- 4.7 L and 18.1 +/- 4.4 L, respectively. This difference is not significant, whereas significant differences were found for all other tested equations. Significant smaller absolute differences between the model 1 equation and deuterium reference results were found when compared with the results of the other three tested equations. Conclusion: When compared with results of the reference deuterium method the physical model 1-derived equation was the only one that provided reliable total body water results by bioelectrical impedance analysis in children