Biomedical subjects

D Möri

Publications and source records attributed to D Möri.

6 recordsLinked to original sources

PubMed2000

Dynamic susceptibility contrast MR imaging of plaque development in multiple sclerosis: application of an extended blood-brain barrier leakage correction.

Since the pathogenesis of multiple sclerosis (MS) lesions is not yet fully understood, we investigated the potential of dynamic susceptibility contrast (DSC) magnetic resonance (MR) perfusion imaging for a better characterization of lesion pathology. Twenty-five MS patients were examined on a 1.5 T scanner. A single dose of gadolinium (Gd)-DOTA contrast agent was injected, and echoplanar images were acquired every 0.5 seconds for 1 minute. From the signal intensity-versus-time curves, the relative cerebral blood volume (rCBV) was evaluated for regions in plaques and in gray and white matter. The rCBV calculated for acute, Gd-enhancing plaques was corrected for the effects of blood-brain barrier leakage, using a new correction algorithm. Acute plaques had significantly higher blood volumes than normal-appearing white matter (P < = 0.01). Chronic plaques that appeared hypointense on T(1)-weighted images had lower rCBV than T(1)-isointense plaques (P < = 0.03). Our results indicate that the acute phase in MS is accompanied by vasodilation. In later stages of gliosis, the perfusion decreases with increasing axonal injury. Although the DSC technique is less sensitive than conventional MR imaging, the information provided is essentially different from that obtained with any other MR method.

Adult↗

PubMed1997

[Convulsive seizure].

A formerly healthy 14-year old boy with difficulties at school was admitted after two generalized seizures. Blood samples taken in the emergency room revealed normal serum-values for glucose and magnesium, but low calcium and elevated phosphorus. First evaluations showed normal age-related psychophysical development, serum-PTH was elevated and serum-1,25(OH)2D was normal. A CT-scan disclosed symmetric intracerebral calcifications. Further investigations confirmed the diagnosis of pseudohypoparathyroidism type 1B. Adequate treatment with calcium and calcitriol normalized serum-calcium, phosphorus and serum-PTH. Interestingly, school performance improved, as did personal activity.

Adolescent↗

PubMed1997

Early evening melatonin and S-20098 advance circadian phase and nocturnal regulation of core body temperature.

The phase-shifting capacity and thermoregulatory effects of a single oral administration at 18 h of melatonin (5 mg) or S-20098, a melatonin agonist (5 or 100 mg), was investigated in eight healthy young men in a double-blind placebo crossover design. The unmasking conditions of a shortened constant-routine protocol (mini-CR) were used to collect evening phase markers of physiological parameters. In comparison to placebo, all three drug administrations induced an earlier dim-light melatonin onset (DLMO), an earlier increase in distal skin temperature, and an earlier decrease in core body temperature (CBT), heart rate, and proximal skin temperature. This indicates that administration at 18 h of both melatonin and S-20098 (more pronounced with 100 than 5 mg) induced an earlier regulation of the endogenous circadian nocturnal decline in CBT. On the posttreatment day a second mini-CR revealed persistent significantly phase-advanced circadian rhythms as estimated by DLMO, as well as by the midrange crossing time of CBT and heart rate decline. There were no significant differences between the two doses of S-20098. The data suggest that, in addition to immediate thermoregulatory changes, a phase advance of the circadian system had occurred and that the phase advance could still be measured on the posttreatment day.

Acetamides↗

PubMed1997

Melatonin and S-20098 increase REM sleep and wake-up propensity without modifying NREM sleep homeostasis.

The pineal hormone melatonin has been implicated in the circadian regulation of sleep. In a crossover design, we investigated the effect of acute administration of 5 mg melatonin and a melatonin agonist (S-20098, 5 and 100 mg) in healthy young men when given 5 h before bedtime on sleep structure and electroencephalogram (EEG) power density. Each trial comprised a baseline, a treatment, and a posttreatment sleep episode. Relative to the placebo condition, all treatments phase advanced the core body temperature rhythm [Kräuchi, K., C. Cajochen, D. Möri, C. Hetsch, and A. Wirz-Justice. Sleep Res. 24: 526, 1995; and Kräuchi, K., C. Cajochen, D. Möri, and A. Wirz-Justice. Am. J. Physiol. 272 (Regulatory Integrative Comp. Physiol. 41): R1178-1188, 1997]. Rapid eye movement (REM) sleep was increased after both melatonin and S-20098. This increase in REM sleep was most pronounced in the first REM sleep episode. On the posttreatment night after melatonin and S-20098 administration, more wakefulness was present in the latter one-half of the sleep episode. EEG power density between 0.25 and 20 Hz during either non-REM (NREM) or REM sleep did not differ from placebo. Thus a single early evening dose of melatonin or the agonist S-20098 increases REM sleep propensity and advances sleep termination while, at the same time, the EEG in NREM sleep remains unaffected.

Acetamides↗

PubMed1996

Daytime melatonin administration enhances sleepiness and theta/alpha activity in the waking EEG.

It is still controversial whether the pineal hormone melatonin can be characterized as a hypnotic. We therefore measured subjective sleepiness and waking EEG power density in the range of 0.25-20 Hz after a single dose of melatonin (5 mg). During an 8 h mini-constant routine protocol, melatonin administered in a double blind cross-over design to healthy young men at 1300 h or 1800 h increased subjective sleepiness, as rated half-hourly on three different scales (Visual Analogue Scale, Akerstedt Sleepiness Symptoms Check List, Akerstedt Sleepiness Scale) and objective fatigue as evidenced by augmented waking EEG power density in the theta/alpha range (5.25-9 Hz). The increase in subjective sleepiness reached significance 40 min and 90 min after melatonin administration (at 1300 h and 1800 h, respectively) and lasted for 3 h (at 1300 h) and 5 h (at 1800 h). The increase in the theta/alpha frequencies of the waking EEG occurred immediately after melatonin ingestion and stayed significantly higher parallel to the higher sleepiness ratings. However, the EEG changes appeared before the subjective symptoms of sleepiness became manifest. There was a significant correlation between salivary melatonin levels and the timing of increased subjective sleepiness. Melatonin had no effects on mood.

Adult↗

PubMed1994

Evidence for the colocalization of parvalbumin and glutamate, but not GABA, in the perforant path of the gerbil hippocampal formation: a combined immunocytochemical and microquantitative analysis.

Gerbils (Meriones unguiculatus) are known for their seizure sensitivity, which is dependent on an intact perforant path from the entorhinal cortex to the hippocampus. In contrast with other species, the perforant path in gerbils contains parvalbumin, a cytosolic high-affinity calcium-binding protein. Parvalbumin is known to be present in a subpopulation of GABA-containing neurons and is thought to be responsible for their physiological characteristics of fast spiking activity and lack of spike adaptation. Therefore, the question arose of whether this projection in gerbils is GABAergic or glutamatergic as in other species. In a first approach to this question, the effect of lesioning the origin of the perforant path, the entorhinal cortex, on levels of GABA and glutamate was determined by enzymatic-luminometric assay in single layers of the dentate gyrus of lyophilized brain sections. Parallel sections were cryofixed using an acidified acetone-formaldehyde mixture at -20 degrees C for 48 h, and subsequently stained for parvalbumin immunocytochemistry. Seven days after ablation of the entorhinal cortex, parvalbumin staining was undetectable in the termination zone of the perforant path, the outer two-thirds of the stratum moleculare. In parallel, glutamate content was reduced to 80% of controls (and of the unoperated contralateral side) but unchanged in the inner third of the stratum moleculare and in stratum granulare. GABA content was not significantly altered by the lesion. From these results, we conclude that in the gerbil as in other species, the perforant path contains glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗