Jeroen ten Haaf

Maastricht University | UM · Library

Getting cited is important for scholars and for the institutions in which they work. Whether because of the influence on scientific progress or because of the reputation of scholars and their institutions, understanding why some articles are cited more often than others can help scholars write more highly cited articles. This article builds upon ea...

Culture influences usability, and usability has influence on learning in a Virtual Learning Environment. When offering ‘e-Learning distance degree programs’ one has to take in account the cultural background of the student population. A mismatch between the culture for witch the Virtual Learning Environment was designed and the students can severel...

Plagiarism is a major concern in the academic environment. Research has pointed out plagiarism detection software outperforms the teachers intuition. There is, however, a difference in source and algorithm used by different plagiarism detection tools; therefore there can be a difference in performance. In 2009 an experiment was conducted at Maastri...

The reliability of measurements of plasma osmolality is known to be biased by technical artifacts, such as the anticoagulant and the osmometric technique used; the resulting measurement errors therefore may cause errors in interpretation of data. In assessing the potential biasing influence of procedural variables, we found that the temperature at...

The influence of age on several parameters related to water balance was studied in Wistar rats. Plasma AVP concentration and plasma osmolality were increased at midday in 21-month-old rats as compared with 3- and 4-month-old rats. Daily water intake per 100 g body weight was reduced in 14- and 21-month-old rats as compared with 3- and 4-month-old r...

Intracerebroventricular administration of dynorphin-(1-13) inhibits dose-dependently plasma vasopressin level in normal as well as in water-deprived rats, whereas systemic (subcutaneous) administration of this opioid peptide is ineffective in this respect. Simultaneous subcutaneous, but not intracerebroventricular, administration of naloxone preven...

Naloxone, haloperidol, and neurotensin suppress ACTH-induced grooming. The suppressive effects of naloxone and of haloperidol on ACTH-induced grooming are observed following subcutaneous as well as intracerebroventricular administration. The suppression of ACTH-induced grooming by these drugs is not accompanied by a change in the relative distribut...

beta-Endorphin (beta E) exerts a strong inhibitory action on plasma vasopressin (VP) of rats, after intracerebroventricular, but not after subcutaneous injection of the drug. This effect is time- and dose-dependent. Also in the water-deprived rat, this treatment leads to a strong decrease of plasma VP levels. When rats treated with histamine (HIS)...

In rats, ethanol has generally been thought to inhibit vasopressin (VP) release into the peripheral circulation; however, the primary evidence for this conclusion has been indirect. Radioimmunoassay was used to measure VP in the plasma of rats decapitated 5 or 60 min after intraperitoneal injection of ethanol (2.0 g/kg). Confirming the popular noti...

We studied the sodium balance and changes in plasma volume by an isotope dilution technique in the first week after an aneurysmal subarachnoid hemorrhage in 21 patients. In 11 of the patients, the plasma volume decreased by more than 10%. This was accompanied by a negative sodium balance and hyponatremia in 6 patients, a negative sodium balance wit...

mRNA encoding the vasopressin-neurophysin precursor was quantitated in individual hypothalamic nuclei of rats by a liquid hybridization assay. Drinking of 2% saline for 14 days, a treatment that increased the plasma vasopressin concentration 9-fold, resulted in a 5- and 2-fold increase in mRNA levels in the supraoptic and paraventricular nucleus, r...

In order to investigate the endogenous occurrence of vasopressin fragments that have previously been found to be generated in vitro by brain peptidases and to have highly potent central activity, extracts of hypothalamus, hippocampus and the pituitary gland were fractionated by high pressure liquid chromatography and analyzed by radioimmunoassay sy...

This study describes effects of various peptides, neurotransmitters and cyclic nucleotides on brain polyphosphoinositide metabolism in vitro. The interconversion of the polyanionic inositol phospholipids was studied by incubation of a lysed crude mitochondrial/synaptosomal fraction with [gamma-32P]-ATP. The reference peptide ACTH1-24 stimulated the...

Intraventricular administration of ACTH1-24 into the rat induced excessive grooming behavior. This response could be blocked by local administration of of neuroleptics into either the nucleus accumbens or the neostriatum. Local administration of [Des-Tyr1]-gamma-endorphine (LPH62-77) but not alpha-endorphin (LPH61-76) in either the nucleus accumben...