Biomedical subjects

A Teelken

Publications and source records attributed to A Teelken.

6 recordsLinked to original sources

PubMed2006

Plasma homocysteine levels in multiple sclerosis.

BACKGROUND: There is evidence that homocysteine contributes to various neurodegenerative disorders, and elevated plasma homocysteine levels have been observed in patients with multiple sclerosis (MS). OBJECTIVE: To investigate if and why plasma homocysteine levels are increased in MS, and whether they play a role in the disease course. METHODS: We compared plasma levels of homocysteine in 88 patients with MS and 57 healthy controls. In the MS group, 28 had a benign course, 37 were secondary progressive, and 23 primary progressive. To explore the underlying mechanisms, we measured serum levels of vitamins B6 and B12, folate, interleukin (IL)-12, tumour necrosis factor (TNF)-alpha, leukocyte nitric oxide production, and plasma diene conjugate levels (measure of oxidative stress). RESULTS: Mean (SD) plasma homocysteine concentration was higher in patients (13.8 (4.9) micromol/l) than in controls (10.1 (2.5) micromol/l; p<0.0001). However, there were no significant differences in homocysteine levels between the three clinical subgroups of MS. Serum concentrations of vitamin B6, vitamin B12, and folate were not different between patients with MS and controls. In the MS group, there were no correlations between plasma homocysteine levels and the serum concentrations of IL-12 or TNF-alpha, leukocyte nitric oxide production, or plasma diene conjugate levels. CONCLUSIONS: Elevated plasma homocysteine occurs in both benign and progressive disease courses of MS, and seems unrelated to immune activation, oxidative stress, or a deficiency in vitamin B6, vitamin B12, or folate.

Aged↗

PubMed2003

Low leucocyte myeloperoxidase activity in patients with multiple sclerosis.

The gene for myeloperoxidase (MPO) has been implicated in multiple sclerosis (MS). By measuring H(2)O(2) dependent oxidation of 3,3'5,5'-tetramethylbenzidine with spectrophotometry the authors investigated MPO activity in peripheral blood leucocytes from 42 patients with MS (12 with secondary progressive MS, 17 with primary progressive MS, and 13 with relapsing remitting benign MS) and 32 healthy controls. Leucocyte MPO activity was significantly lower in patients with benign MS (mean (SEM) 0.086 (0.029) U/mg protein; p<0.01), secondary progressive MS (0.038 (0.009) U/mg protein; p<0.001), and primary progressive MS (0.057 (0.016) U/mg protein; p<0.001) compared with healthy controls (0.322 (0.053) U/mg protein). These data suggest that low MPO, which may be genetically determined, plays a part in MS pathogenesis.

Adult↗

PubMed2001

Cooling garment treatment in MS: clinical improvement and decrease in leukocyte NO production.

Ten heat-sensitive patients with MS were randomly allocated in a cross-over study to wear a cooling garment for 60 minutes at 7 degrees C (active cooling) and 26 degrees C (sham cooling). In contrast to sham cooling, active cooling improved fatigue and postural stability with eyes closed and muscle strength. There was no decrease in tympanic temperature, but active cooling was associated with a 41% decrease in mean leukocyte nitric oxide (NO) production (p = 0.004). This effect on NO could be relevant because it blocks conduction in demyelinated axons.

Adult↗

PubMed2000

Insulin-like growth factor II receptors in human brain and their absence in astrogliotic plaques in multiple sclerosis.

Insulin-like growth factor (IGF) II receptors were studied in human adult brain by using autoradiography with [125I]IGF-II. Receptors were found to be widely distributed throughout all neuronal regions. The highest densities were found in plexus choroideus, granular layer of the cerebellar cortex, gyrus dendatus and pyramidal layer of the hippocampus, striatum, and cerebral cortex. White matter was devoid of IGF-II receptors. We also examined [125I]IGF-II binding in six plaques of multiple sclerosis, which were characterized by a dense network of astrocytes. We were unable to detect IGF-II receptors in any of the astrogliotic plaques, suggesting that IGF-II receptors in human brain are not involved in astrogliosis. The regional variations in neuronal distribution of IGF-II receptors suggest involvement of IGF-II in functions associated with specific neuronal pathways.

Aged↗

PubMed1999

Peptidylarginine deiminase activity in postmortem white matter of patients with multiple sclerosis.

The myelin sheath in multiple sclerosis (MS) appears to contain a higher proportion of the citrullinated isoform of myelin basic protein MBP-C8. In vitro, MBP-associated arginine is deiminated to citrulline by the enzyme peptidylarginine deiminase (PAD). We investigated PAD activity in white matter from postmortem human brain samples by measuring the formation of citrulline from benzoylarginine ethyl esther. PAD activity in MS white matter was not different from that in controls. In neonates, in whom MBP is exclusively of the C8 type, white matter PAD activity was not different from that in adults. Our results suggest that in human brain either PAD plays no role in the formation of MBP-C8, or there may be a better accessibility of MBP in myelin in neonates and MS to the enzyme.

Aged↗

PubMed1998

Insulin-like growth factor system in serum and cerebrospinal fluid in patients with multiple sclerosis.

The insulin-like growth factor (IGF) system influences oligodendrocyte survival, myelination, and immune functions. We examined whether alterations in the circulating IGF system occur in multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the central nervous system. We measured concentrations of IGF-I, IGF-II, and insulin-like growth factor binding proteins -1, -2, and -3 in both serum and cerebrospinal fluid from MS patients and age- and sex-matched controls. IGFBP-1 was not detectable in cerebrospinal fluid. We found no significant differences in any of the other components between patients with MS and controls.

Adult↗