A Torremans
University of Antwerp
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Publication
Featured researches published by A Torremans.
Journal of the Neurological Sciences | 2005
A Torremans; Bart Marescau; Ilse Possemiers; Debby Van Dam; Rudi D'Hooge; Dirk Isbrandt; Peter Paul De Deyn
Deficiency of guanidinoacetate N-methyltransferase (GAMT) is the first described creatine (CT) deficiency syndrome in man, biochemically characterized by accumulation of guanidinoacetic acid (GAA) and depletion of CT. Patients exhibit severe developmental and muscular problems. We created a mouse model for GAMT deficiency, which exerts biochemical changes comparable with those found in human GAMT-deficient subjects. CT and creatinine (CTN) levels are significantly decreased and GAA is increased in knockout (KO) mice. In patients, other guanidino compounds (GCs) appear to be altered as well, which may also contribute to the symptomatology. Extensive evaluation of GCs levels in the GAMT mouse model was therefore considered appropriate. Concentrations of 13 GCs in plasma, 24-h urine, brain and muscle of GAMT mice were measured. We also report on the detailed behavioural characterization of this model for GAMT deficiency. Besides an increase of GAA and a decrease of CT and CTN in plasma, 24-h urine, brain and muscle of KO mice, we observed a significant increase of other GCs in brain and muscle that was sometimes reflected in plasma and/or urine. KO mice displayed mild cognitive impairment. In general, it could be concluded that the GAMT mouse model is very useful for biochemical research of GAMT deficiency, but shows only a mild cognitive deficit.
Amino Acids | 2003
A Torremans; Bart Marescau; Raymond Vanholder; R De Smet; J.M. Billiouw; P.P. De Deyn
Summary. There are no reliable mean values of NG-monomethylarginine (NMMA) in blood and urine of patients with renal insufficiency available in the literature. Therefore we investigate whether the NMMA levels are changed in blood and urinary excretion of nondialysed and dialysed patients with chronic renal insufficiency to evaluate whether NMMA may reach sufficiently increased concentrations in blood of the patients to exert toxic biological activity.In nondialysed as well as in dialysed patients we find no significant difference in serum concentration of NMMA between patients and controls. In nondialysed patients (all with a residual creatinine clearance lower than 15 ml/min), we find 94.5 ± 26.1 nM (mean ± SD) versus 94.6 ± 19.5 nM in controls. Similar levels are found in serum of haemodialysed patients (each with serum creatinine levels >700 μM): 83.0 ± 20.2 nM. The urinary excretion of NMMA in nondialysed patients is also not significantly different from the excretion of controls: 123 ± 110 in patients versus 157 ± 117 nmol/24 hrs in controls. Furthermore, the clearance of NMMA is much lower compared to the clearance of the dimethylarginine derivatives.Based on the literature, the low nanomolar levels of NMMA found in blood of patients with renal insufficiency do not support the statement that NMMA proper may act as a uremic toxin.
Brain Research | 2004
A Torremans; Rudi D'Hooge; G Van de Vijver; Bart Marescau; Raymond Vanholder; Norbert Lameire; P.P. De Deyn; P.P. Van Bogaert
Uremic retention solutes possibly contribute to neuronal hypoxia/ischemia and its consequences in patients with renal failure. We examined the in vitro effects of several uremic retention solutes on murine central neurons under chemically induced metabolic hypoxia by application of sodium cyanide (NaCN). Whole cell currents were recorded using the tight-seal whole-cell voltage clamp technique. Application of NaCN caused an inward whole-cell current. From all tested toxins, which included several indoles, guanidino compounds, polyamines, purines, phenols, DL-homocysteine, orotate and myoinositol, only creatinine (CTN), guanidine (G) and guanidinosuccinic acid (GSA) produced a significant current in control and hypoxic neurons. Current evoked by GSA was significantly increased in the chemical hypoxic condition, and a synergistic effect of GSA and spermine was observed in hypoxic neurons.
Kidney International | 2005
Sunny Eloot; A Torremans; Rita De Smet; Bart Marescau; D De Wachter; Peter Paul de Deyn; Norbert Lameire; Pascal Verdonck; Raymond Vanholder
American Journal of Kidney Diseases | 2007
Sunny Eloot; A Torremans; Rita De Smet; Bart Marescau; Peter Paul De Deyn; Pascal Verdonck; Raymond Vanholder
Kidney International | 2006
A Torremans; Bart Marescau; B Kranzlin; Norbert Gretz; J-M Billiouw; Raymond Vanholder; R De Smet; K Bouwman; Raf Brouns; P.P. De Deyn
Physiology & Behavior | 2005
A Torremans; Bart Marescau; Debby Van Dam; Chris Van Ginneken; Frans Van Meir; Pierre-Paul Van Bogaert; Rudi D'Hooge; Jan de Vente; Peter Paul De Deyn
Renal Week 2004 | 2004
Sunny Eloot; Rita De Smet; A Torremans; Dirk De Wachter; Bart Marescau; P.P. De Deyn; Pascal Verdonck; Raymond Vanholder
Merican Society for Artificial Organs Journal | 2005
Sunny Eloot; Rita De Smet; A Torremans; Bart Marescau; P.P. De Deyn; Pascal Verdonck; Raymond Vanholder
Hemodialysis International | 2005
Sunny Eloot; R De Smet; A Torremans; D De Wachter; Bart Marescau; P.P. De Deyn; Pascal Verdonck; Raymond Vanholder